The only reason I could think of for prohibiting gift cards/certificates is that you can use them to get around some of the restricitions listed above. We've all read threads here where people have bought gift cards and then went on a blacked out day, or used a coupon. This place near me has a 20% coupon in a mailer and it would be sweet to buy gift cards and then use the coupon (if that's even allowed by the restaurant.)

I have yet to have a gift certifcate not post, but I'm still weary about getting a gift card to fulfill my $125 needed spending for the UA bonus. I've only bought cards to meet this promotion at places where I have no problems getting auto credit for the certs in the past.