P&S's allowed at events but no DSLR's??

I just shot a monster truck show the other day at the local sports arena. I got a free ticket and access to a private suite. Thought it'd be fun to photograph too, so I figured "why not?"

As soon as I got to my seat, I took my gripped 7D + 70-200mm f/2.8L II IS out of my bag and started snapping away. 5 minutes later, an arena official came up to me and asked if security at the arena entrance said anything to me about my gear when I brought it inside. They didn't see it because I was wearing a photo backpack, so I told him "nope" (which was the truth) and he said "ok" and went away with a puzzled look.

5 minutes after that, another arena security official came up to me and told me I wasn't allowed to use the camera. When I pointed out to her that half the people in the arena are using cameras (including the woman right in front of her with a Canon SX30) she told me "well your camera is a lot nicer and can zoom in closer than those, so we can't let you use it."

So 1 more visit from arena security and several arguments later, they finally agreed that I could use my camera but as long as I kept the 50mm lens on it. Apparently my EF-S 17-55 f/2.8 IS was too much for them as well, same for my 100mm f/2.8L macro.

So is it normal for arena events to have anti-DSLR policies like this or were these people just stupid.