When times are bad...
When economic times are bad, more companies looking to survive resort to intellectual property lawsuits.

Proprietary is no panacea, but the GPL protects
Microsoft has recently lost a number of patent cases over third party patent "violation. Most proprietary software as well as Microsoft's, are licensed in such a way that negates the ability to sue the vendor...

http://www.cyber.com.au/cyber/about/comparing_the_gpl_to_eula.pdf

ALSO, THERE IS NO WARRANTY OR CONDITION OF TITLE, QUIET ENJOYMENT, QUIET POSSESSION, CORRESPONDENCE TO DESCRIPTION OR NON-INFRINGEMENT WITH REGARD TO THE PRODUCT.

Analysis
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Also, Microsoft disclaims that this software will not infringe on the intellectual property rights of others. This is a potentially serious issue, as has been recently shown through the legal dispute between Timeline Inc. and Microsoft. Timeline has won a recent ruling which exposes all Microsoft SQL Server developers to a serious patent encumbrance.

When it comes to rogue third party patent threats, you are no better off with proprietary licensed software than you are with open source licensed software.

The Timeline Inc case bring up an important issue; while no vendor can expected to identify all potential patent violation when developing software, when they do purchase and license technology from a third party, they vendor should insure that the end user/develop is not put at further risk.

If the issue is the threat of lawsuits over intellectual property then corporate America and everyone else are actually in a better legal position using GPL'ed Linux than using Microsoft's products as a development platform.

Microsoft has a history of licensing third party code and patents in such a manner that still leaves developers exposed. Even going back to the LZH/GIF Unisys patents,
http://www.unisys.com/about__unisys/lzw/
"Microsoft Corporation obtained a license under the above Unisys LZW patents in September, 1996. Microsoft's license does NOT extend to software developers or third parties who use Microsoft toolkit, language, development or operating system products to provide GIF read/write and/or any other LZW capabilities in their own products (e.g., by way of DLLs and APIs)."

Microsoft also licensed database technology for Microsoft's SQL server from Timeline Inc, under similar license terms as did with Unisys. This license did not grant Microsoft the right to sublicense to third party developers to extend functionality, in some cases even restricting the use of visual basic. Unlike companies like Oracle Corporation and others, Microsoft chose a cheaper option for the license which left third party developers, users of Microsoft SQL Server,Office and other Microsoft products at risk of being sued by Timeline Inc for violation of Timeline Inc patents. Timeline Inc asked Microsoft to upgrade to a similar license used by Oracle, but Microsoft refused, so the whole issue went to court and in 2002, Timeline Inc won.
http://www.timeline.com/021903PR.htm
http://www.theregister.co.uk/content/53/29419.html

While SCO has yet to provide any publicly available substantial evidence in their case against IBM and Linux, Timeline Inc has already won a US Washington Court of Appeal judgment against Microsoft in another contract dispute.

How many other cases exist where Microsoft has included third party technology in it products, but has also taken the cheaper licensing option and left developers and even users exposed to the threat of lawsuit? Due to the closed nature of the proprietary business model, how can third party developers even check?

Microsoft's products and platforms do not provide users and developers an absolute safe haven from the threat from lawsuits based on violations of intellectual property. Microsoft's EULA ( End User License Agreements ) provide the developer and end user with no protection against threat from current or future intellectual property lawsuits.

The Gnu General Public License (GPL) and Gnu Library General Public License (LGPL) are based on years of solid legal research.
http://www.gnu.org/philosophy/enforcing-gpl.html

Since The SCO Group has knowingly sold and distributed the GPL licensed Linux kernel and other components, it must by the terms of the GPL license, provide all those who receive the code from them an implicit license to use any intellectual property, patents or trade secrets which SCO owns and is used within the GPL'ed source code. That implicit license to that SCO intellectual property is also granted to anybody who subsequently receives the GPL source.
http://www.gnu.org/licenses/gpl.html

The GPL only grants the right, for reasons of intellectual property infringement or contractual obligations, to stop distributing the GPL'e binaries and source code if the conditions are imposed upon you by a third party. Since The SCO Group claims ownership the intellectual property in question, it must grant all subsequent recipients of the GPL licensed source code The SCO Group has distributed and any GPL'ed derivative, the same implicit license and right to The SCO Group's intellectual property the code imposes upon.

The SCO Group has acknowledged deals with Suse and Lindows to distribute SCO's intellectual property in GPL'ed Linux, and has now stated that it will not prosecute a case against anyone who purchase Linux from The SCO Group. However the GPL license does not grant anyone or any third party organization the right to append extra terms and conditions upon the recipients of the GPL licensed source code.

It is very easy to effectively fold the current development branches of the Linux kernel and any other GPL'ed code back into SCO's distributed GPL'ed sources. This would grant the same implicit license for the infringed SCO intellectual property to the all the current development.

In 1994 a group of Novell alumni formed Caldera Systems International with the backing of Novell's founder Ray Noorda. It is Caldera systems which purchased the "rights" from Novell for SCO and in May 2003 became the current SCO Group. Caldera have since 1994, before the OLD SCO instigated the Project Monterey deal with IBM in 1998, released all it's Linux kernel code and other projects and contributions under the GPL licenses. The GPL licenses are an effective copyright contract strictly controlling the terms and conditions of distribution of both binaries and source. Caldera and therefore new SCO group have been collectively developing and selling under the terms of the GPL "contract" prior to the OLD SCO deal with IBM. There is no way that that the current SCO Group can claim to be unaware of the implications of the full terms and conditions of the GPL license.

Both Old SCO and Caldera actively participated in the development of the same Linux enterprise features that the current SCO Group are suing IBM over.
http://twiki.iwethey.org/twiki/bin/view/Main/TrillianProject

Read the OSI Position Paper on the SCO-vs.-IBM Complaint
http://www.opensource.org/sco-vs-ibm.html
The SCO Group do not have much of a case to speak of.

In fact:
http://www.opensource.org/sco-vs-ibm.html#ip_theory

Since the dispute has moved to Federal court, it is now within the court's purview to rule on more general issues of intellectual-property law as they pertain to this case. OSI pleads to the court to find as follows:
* To find that claims of trade secrecy in software are incompatible with a routine business practice of selling the source code licenses to that software to educational institutions or for use as training materials. (Techniques commonly taught in classrooms cannot be considered secrets.)

* That any software vendor, having participated in an open-source commons and benefited from the products thereof, is estopped from claiming proprietary rights that would prevent other participants from symmetrically collecting that same benefit. (If you drank from the well, you don't get to poison it.)

* That the GNU General Public License under which Linux is issued is in fact a valid license and does create binding legal obligations on those who accept its terms.

You are in a better legal position using the GPL'ed Linux platform and other GPL'ed software, than you are using Microsoft's or any other closed source software. The GPL license attempt to insure that all involved in developing, selling, distributing or just using GPL'ed products, have the right to use and extend the source code under the same terms of the GPL license.

Read about the Trillian Project which ported Linux to Intel's IA-64 processors, including the admission from then Caldera CEO Random Love
http://twiki.iwethey.org/twiki/bin/view/Main/TrillianProject

When times are bad...
The only upside with lawsuits is to someone with a deep pockets and win.

I don't see how you can win by suing open source projects.

When times are bad...
That's not the only upside!! I sure hope you are not a lawyer. :)

Another obvious upside for a proprietary software vendor is to shut out competition from the open-source market.