Obviously I don't expect them to do a point by point comparison of the signature, but they are supposed to at least make sure it's there. Writing 'Check ID' should get them to check my ID every time, but so few even look at the card.

This is a funny prank where a guy went out trying to get people to actually look at the back of the card :)

http://www.zug.com/pranks/credit_card/index2.html