This is the most likely scenario honestly. I was a security guard while I was in college because it gave me time to study. They were very explicit about NOT engaging with anyone in a confrontational manner. You make yourself seen to prevent stuff walking off of job sites and if you see someone doing something you call the police, period. They didn't want to be sued. They even had a limit on how big your mag-lite could be so it wouldn't be considered a weapon.

Or get the courts to give you special liability protection as agents of the state.