I hope this is not off topic... are 100-400 lenses not allowed in most arenas because of competition with pro photographers? I was told my camera was too professional looking in Madison at the Kohl Center for a Men's basketball game. However, after I walked back to my car and removed the 100-400, I was allowed to bring in the camera with a 50. I bought and paid for a ticket to sit in the stands not under the basket. Thoughts would be appreciated. There were others with larger lenses and no credentials around their neck and a couple of others with 70-200s or 100-300s sitting closer than me.
Staying off-topic since its an old thread...
Most of the venues that I have attended in the past specify limits based on size/length, not based on looking professional. I've always assumed that this is due to the fan experience in the stands; a non-photographer sitting behind you doesn't want your large camera lens blocking their view for half the game, and he's plenty entitled to the view from the seat he/she paid for.
When you're in the stands I've never really thought of it as competition with the pros, but more-so about how your equipment deters from the experience of the fans around you. The photo enthusiasts on this site might not care, but I could see it being almost(ok, not quite) as annoying to a non-photographer as that guy in front of you waving a foam finger in your view all game.