Bottom line - fans don't interfere with players. The guy should NOT have been sweeping his hand down there for whatever reason...that ball was fair (as opposed to fans swooping down for a foul ball, which is fine). That notwithstanding, from the angles I've seen, he did brush Shef's face, which certainly entitles Shef to the push in response. He didn't throw a chair, or bottle, or anything. He pushed the guy away from him, and then security stepped in.

Personally, if that guy wouldn't smacked me in the face, I would've beaten his Boston-loving ass 'til it was as red as their namesake. The Boston fans are worse than everybody else, get that through your Padilla-adoring skull once and for all. :p