Having Microsoft say that you can't run FoxPro on a Linux platform is the same as Sony telling you that its against the law to view a Sony DVD except for on a Sony DVD Player.
But isn't that precisely the rationale behind CSS and Region coding, as well as most of the DRM technologies that are still in their infancy? To tell you when, where, and on what kind of player you can play your media? If I can create a proprietary encryption format that requires a license fee to decrypt (e.g., CSS), that would allow me to a) effectively dictate who can and can't enter thet player market, and b) make money from a competing manufacturer's players. So I think that can and is being done to a large extent.

Is it possible that at some point in the future Microsoft may adopt a CSS-style licensing scheme for the Win32 API itself and require huge license fees for the right to execute Win32 binaries? Considering how little challenge the legality of CSS has really had, I wouldn't be surprised to see them try it as a way to kill projects like Wine, or at least make a few bucks off of them.

I think that if there is an assumption by both the vendor and the consumer that nobody reads the EULA in the first place they fail to hold any weight in court. Any lawyers or judges on this list that can support or deny this?
I think there's a pretty good argument that EULAs may constitute contracts of adhesion, which are legally binding but generally frowned upon by the legal system. In a contract of adhesion, one party holds all the bargaining power and offers a form contract with boilerplate language on a take-it-or-leave-it basis, with no opportunity for amendment. If in addition to being a contract of adhesion, the weaker party has no realistic alternatives and is forced to either accept the unfavorable terms or do without, and the agreement is found to be so substantively unfair as to "shock the conscience" of the court, it will likely be held unenforceable.

If I am passing through the desert and find a man dying of thirst, I can offer him an agreement to sign over all his worldly possessions to me in exchange for a drink of my water, and he can accept or decline. While it is a legally binding contract in form, any attempt to enforce the agreement in the US or UK would almost certainly be thrown out as being unconscionable.

So I think any challenge to a EULA would be very fact-specific and would hinge on the extent to which the vendor was in a position to strongarm the consumer. If you have a choice between 2 comparable pieces of software, one with an offensive EULA and one without, I think you would have a tough time claiming unconscionability because the element of choice is there. But if you consier a web page that can only be viewed with a specific browser plugin, the EULA of which gives the vendor the right to install spyware and examine your address books, I think it becomes much more analogous to the man in the desert. I think I could craft a pretty strong argument that such an agreement was unenforceable on those grounds.

But like I said, this is all first year law school theory and I don't know that it has ever actually been put to the test. Then again, commercial law has never really been my area of practice, so I wouldn't necessarily know if it had.