Bob Pivoroff sent this one in:

There was an incident tonight at the St. Louis Airport. C.M. Punk was coming into town from the show tonight in Omaha. A fan asked Punk for an autograph and Punk turned him down. We don't know the story behind it other than apparently the fan may have been rude in his approach.

But this led to another fan yelling at Punk and causing a scene at the airport. This wound up with Punk throwing the man's autograph book in a garbage can. The next thing you know, airport police are there with Punk and the guy, with Punk very annoyed at having his time wasted. Other WWE wrestlers were asking fans if they knew "the fat guy" (the guy whose book Punk threw in the garbage can). Punk later went on Twitter and made a mention of "unacceptable behavior" and "One person ruins it for everyone" saying he wanted to thank all the respectful fans at the airport tonight and how he just doesn't like rude people.