I'm really interested if any case makes it through court.
Want to see a violation of the GPL? Log into any mud, and request the source for it.
See what they say.
Most Muds are based on MERC or DIKU. All of them are derivations of a GPL'ed source. I used to have a great time explaining to mud admins that they need to release the source for the mud. They ALWAYS get really pissed. Some even "claim" to call a lawyer on it. Its great fun if you're bored (I used to do it in school, and tried it today, because of a long compile)
Some things never change, I guess...