Please oh Please for the love of all the deities in the multiverse tell me you did not just use "the way it has always been" to justify denying your rights! Oh, and I'll give two examples that I've played in the last month:
Star Wars Battlefront (I think Battlefront 2 did use key checking, but not the original) and my personal favorite right now Star Wars Empire at War.
I've played both of those games recently with another copy on the same computer (mostly to test mods I'm working on).
I'm not talking about the age old question of logging into some master server and restricting cd keys there, because that in most games uses an IP/key check, and some will quietly allow two games from the same IP with the same key through (some won't, but some will, don't exactly have a list or anything right now).
A lot of games limit access to THEIR servers to one client per key, and you know what, so be it. Their server is not part of the package I purchased, if they want to limit access to their server, that IS within their rights, and IS NOT a violation of mine. However, restricting the way I can play with this game on a single computer IS violating my rights.
If people stood up for their rights more often, we wouldn't have our network rights being trampled in an aimless attempt to stop piracy such as Sopa or Pipa. Anyone who thinks those would stop piracy is stupid and knows nothing about the internet, but it would certainly stop a lot of legitimate sites overseas where there isn't currently a quality "infringement takedown notice" system. If any of the sites you like to frequent are overseas and someone posts illegal materials on those sites, under Sopa and Pipa, that site would be blocked in the USA. Talk about violating rights. But hey, if you want your rights violated, go ahead, get in line, call your congressmen and tell them that you're perfectly happy making fair use illegal, eliminating your choice of websites to go through, hell, let's tell them to force us to use only RIAA approved search engines, and while we're at it, let's take down IMDB because it has, you know, quotes of copyrighted material on it. Oh wait, let's go one step further, let's eliminate free speech so that in the future, I can't make this declaration of my desire to keep my rights.
P.S. If any of the above annoys, angers, offends, or in any other way hurts you, I apologize. I can get pretty militant when I see my rights being restricted. Of course, it amazes me when other people DON'T get pretty militant, but in respect to the rights I hold so dear, it is your right (at least for now) to not protect your rights.