if you've read anything at all about bush's "public" appearances, you'll surely know that although they are totally funded with taxpayer money, they aren't really public at all... they're meticulously screened and quintessentially private, and the gop can and will kick out anyone who strikes them as remotely non-reactionary. "young democrats" t-shirt? sorry, young democrats don't deserve to get to hear their president speak. anti-war bumper sticker? get outta here!
bush lives inside a bubble, shielded from those who so much as disagree with him on policy issues. this is probably why he was so awful during the presidential debates: it was the first time in four years that he'd actually been challenged face to face, and he didn't know how to cope with it.
dkos has a great letter from three people who were kicked out of a recent bush pep rally in denver... and who actually got some answers as to why they were booted:
The Secret Service also revealed that ticket distribution and staffing of the Social Security event was run by the local Republican Party. They wanted us to be clear that it was a Republican staffer - not the Secret Service - who kicked us out of the presidential event. But this revealed something else that should be startling to all Americans.