In high school I worked in a McDonalds. There was actually a poster in the back that said cameras were not allowed on the property. This was around the time of 'Supersize Me'.

I don't remember exactly what the instructions said employees were supposed to do. I believe it was asking people to leave and refer them to McDonalds corporate PR for requests to take pictures. It definitely didn't say assault them.

Clearly these guys were acting way outside of what McDonalds intended for them to do, but I think McDonalds' silly 'no cameras' policy might have incited them.