If it wasn't posted as homework, that is to say no one knew where the question was coming from, wouldn't it still be an interesting discussion? Who in the technical field hasn't had to deal with troublesome performers?
As a teacher, I dislike how actors are babied. Too many theaters, agents, and parents simply
enable 'artists' to behave this way. I'll brag and say I don't have that many problems with my students because I train them to have different expectations. Short of headlining professionals, the average performer simply isn't important enough to be as demanding as many think they should be. As a building manager I politely and professionally don't allow poor behavior from renters either.
Start with written policies, including
call times, conduct, and forbidden actions like playing with
props and touching the
cyc. These should be presented to the cast at some
point, preferably from someone in charge. If you or the director do this at an early meeting you'll solve the majority of problems, since most people are programmed to follow the rules. If someone breaks a rule, have a policy you can't
point them to ("Hey, remember what we talked about at that first meeting last week?").
When someone breaks the rules, use the theater chain of command. Whoever is overseeing the actor at that time (costumes,
props, SM, director,
etc.) needs to politely and respectfully
call them on their mistake. If that doesn't correct the problem, pass it up to the next person in charge (probably SM or director). Third time in my theater is typically a "Come to Jesus meeting." That is to say, it's our way or the high way. All of this depends on the nature of the infraction, of course. Reinforce the authority of the person overseeing the problem.
It helps to talk to people one on one, so they don't lose
face with their peers. If you respect them and explain why a rule exists, I find that most of the time they understand why they need to comply. Make sure there is some sort of consequence - we make late performers sweep and mop the
stage, or sort screws where they can't hang out with their friends.
That sounds really grumpy, but I find that I typically have a much smoother rehearsal and production period, and generally a more positive and professional attitude backstage than I would if I didn't set policies. We rarely have equipment misused, or actors fooling with things they shouldn't, and I like to believe my actors go out into the world and impress future technicians and SMs with their behavior.