We created a verbal contract with our actors. The contract was this: they show up all nights, on time, and stay until closing... in return they get paid for all that time at the end of the season. If they didn't show up then the contract was broke and there wouldn't be a pay day at the end.
Of course, there were some exceptions. Some people had something important come up they couldn't avoid. However, due to the initial face-to-face agreement we made, not one of the 45 paid staffers just didn't show up, arrived late, or left early without telling us. At the end we paid everyone for their time regardless. Even the guy who stole some of my masks (didn't have sufficient proof) and got high and left early. Even if someone had quit mid season (which no one did) we were going to pay regardless if they got aggressive or had a good story.
The idea was that the possible threat of not being paid for breaking our verbal contract kept everyone honest. It worked for us.