hedwards: I'm pretty sure that he'd have to do that in Seattle if he wanted to, Valve is located a few miles from where I live and that's going to be the appropriate venue for any litigation. Suffice it to say our courts are pretty friendly to Valve, MS and Nintendo otherwise they wouldn't have corporate offices here.
As much as I dislike it, it's only slightly less disgusting when customers abuse jurisdiction like that then when corporations do.
Well, it depends on your legel system of course, but normally the place of legal action is the residence of the consumer.
Last time Valve was sued in Germany, the proceedings took place in Hamburg.
SimonG: Do you know if that person tried any legal action? Damages might be hard to get, depending on the legal system, but a cease and desist (or equivalent) against Steam should be within the possibilities.
Psyringe: Steam's license covers that. By agreeing to the license, people agree that:
1. Steam may them lock out of their accounts whenever it feels like it
2. Their only valid course of action if they are dissatisfied with Steam in any way is to leave Steam
3. If any matter goes to court nevertheless, it has to go to court in the US, specifically in King County in the state of Washington (and is resolved according to the law of this state).
Of course, one could then try to refute the license. But whether that has any chances of success depends pretty much on where you live. In any case Steam's usual reply to such matters is "We are resolving legal matters according to the license you agreed to", and this license grants Steam a carte blanche (which doesn't seem to bother people _until_ they have their accounts locked, but it's a bit late then).
Well, it's a good thing then, that the licence is not (fully) legal in Germany...
Edit: I've I got some free time at work tomorrow I will read the verdicts of the Half Life cases, would be nice to see what Valve had to say for themselves ... ;-).