The new game Batman: Arkham Asylum uses a fancy new copy protection scheme. In addition to the usual copy protection fare, this game hooks in additional check that occurs during gameplay. If the game has been cracked (had the copy protection removed), it will disable Batman's glide ability, effectively halting the player's progress through the game. What's curious about this is that the game never actually announces to the player that they've been caught trying to pirate the software -- it just appears that Batman can't proceed for some unknown reason.
One illegitimate user has already been caught by outting himself on the official support forums: http://forums.eidosgames.com/showthread.php?t=95030.
I'm left a bit puzzled about the efficacy of this copy protection strategy. Certainly, it will reduce the number of players who are able to enjoy the game without paying for it. It also wastes the time and bandwidth of the would-be pirates who download the game illegally, which is at least a moral victory. However, this system does very little to turn pirates into customers. In fact, I believe it may have an opposite effect.
Because the software doesn't explicitly notify the user that their copy is believed to be illegititmate, players are likely to blame the problem on a bug in the software. Because most stores don't accept returns on opened software items, it is unlikely that a user would risk purchasing the software in order to fix the problem. In fact, I believe he's more likely to tell his friends that the game is buggy and discourage them from purchasing it as well. If they continue to have this experience with software, they'll become less and less likely to buy products in stores. In the long run, this distrust can be hurtful to the entire industry.
While I'm definitely in favor of having a layered copy protection scheme, I think that covert copy protection is a sad, sad mistake. Instead, why not pop up a message to let the player know they won't be able to proceed until they legitimize their copy? You still get to play a gotcha on all the crackers -- they'll have to play through the entire game to make sure it's clean -- and you get to clearly tell your early adopters that you welcome them as customers more than you despise them as pirates.