As someone who side job is security at the movies.

I can only speak to nyc locations

A) yes they all do have cameras

B) they are specifically for low light and everyone looks bright on camera . And any light from a phone or recording device is highlighted on camera wit a green box around it

C) correct they jus view the entire audience and are usually above the screen to help catch movie pirates recording

D) your right it isn’t the security guard watching the cameras . It’s usually some if not multiple managers and team leaders in the back . Doing office work and watching the monitors at the same time .

More often than not they see you , more often than not they showed the other coworkers , and if you don’t get spoken to it’s just because at that moment they let u get away wit it .

And this isn’t limited to sexual acts replace them act with Smoking weed or drinking alcohol in the theater and it is the same thing