This will fool them!

There is no beep thing. There's a camera on top where that height limit bar thing is.

I work at a fast food restaurant. It beeps when a car drives up

Oh. But there's also a camera right? Every one I've seen has a camera. Maybe there's a beeper in conjunction?

I have never seen or heard of drive thru's with cameras. Except ones with double lanes to keep track of which car is what order.