I get few invites anymore, but it seems the majority of the card invites are to sub-sub-prime cards. Cards that have fees well over $100. When searching for new victims I'd think they would have a line like: If card = Amex then response = 0. At least rule out someone with a large amount of TLs. Oh well, the shredder gets hungry too!
WaMu seems to be a lot sloppier than the others in hiring out their pre-approval business.