Merandab4 - While I totally agree with you, I just want to warn you not to post a strongly-worded post about this on any of the traditional wedding message boards unless you're wearing a fire-proof suit!

I've seen it get pretty ugly about this topic, usually because somebody posts something along the lines of "we're going to put the registry cards in with our wedding invitations, that's okay, right?" and then gets mad when people tell them it's not okay. I've never had trouble finding somebody's registry - hit Burdines/Macy's, Target, and Bed Bath & Beyond, and I'm bound to find something if they registered at all. If that doesn't work, then I'll ask them.
My understanding of the etiquette is that it's okay to include them with shower invitations because the whole purpose of a shower is a gift party. However, that's not the main purpose of a wedding (we hope!) so that's why it's not proper etiquette-wise to include the cards. To me, the decision is simple: include the cards and some of your guests will be offended while some will not care, or don't include the cards and no one will know the difference. In the end, why choose something that you know will offend people and make them feel like you're more worried about their presents than their presence?
If it's still bugging you, check out etiquettehell.com and read over some of the stories where people actually printed requests for cash on the wedding invitation. That'll make you feel better about the people who put the cards in their invitations
