Does the D3100 count as a professional camera?

I'm going to a concert and their camera policy says no "professional" cameras. Does the Nikon D3100 count as a professional camera?

I believe any camera with a detachable lense (dslr camera) are considered 'professional'

Depends on the security at any specific concert but as a rule I'd assume a "yes". Get a small point and shoot with a fast lens.

Yes in most venues it would. Copyright laws are a big deal. If they don't take it from you they'll make you leave and return the camera to your car.

Not in the world of photography but I'm sure Concert security would consider it "professional".

There are no professional cameras but your D3100 will be banned in concerts.