Your ticket level and the type pass you hold determine which side of this window you are on. Called "the fishbowl", it was put in on the "fanzone" side of the garages to keep people from wandering around in the way of the teams. The bottom of the window has a slot so you can pass items through for autographs.
Having worked at an active race before, I did my best to respect my privilege. I stayed out of the way and never asked anyone who was working for an autograph. Can't say the same for some others.
I saw a mechanic ask a guy to leave the garage area... right after the guy opened the door of the DP car and proceeded to poke around with stuff in the cockpit. Duuhhhh....
I think I would have taken a sterner approach.