When did it become ok to include a "wish list" on a B-day invitation?

We have recently rec'vd 2 seperate (no connection between these families) e-mail invites for kids b-day parties. I'm fine w/the e-mail aspect, but one listed about a dozen things the kid likes, one of them being Nintendo DS games (they about $50 a pop) and the other requesting gift cards or cash in place of a gift. Mind you, these are schoolmates of my kids (one's not even friends w/my kid). I always tell my kids that they should never EXPECT a gift, but should be thankfuil for whatever somebody decides to give them. Kids usually know what other kids like; this has never been a problem. If somebody wants gift ideas, they usually ask; I find that in much better taste. The list only makes sense for family/relatives. This was unheard of when I was a kid...why do people think this is acceptable?