CCW instructors what would you do if a student showed up to range qualification with an AR pistol?

I'm talking fully accessorized AR pistol, stabilizer brace, red dot, the whole 9 yards.

I'm certainly not looking to do this. My state's range qualification is already stupid easy as is. I've always just been curious. I asked my instructor about this and he said he wouldn't allow it, but I'm curious what other instructors have to say.