Who are you to decide? Those that were posting didn't seem like their time was being wasted. Most people are grownups = they can decide for themselves if there time is being wasted. They don't need someone to tell them that. As I recall, from using the contract, private screenings weren't forbidden. The intention is to put it up on the web. If you are screening it and charging tickets, that's when SAG might have a problem. Of course, I don't know what part of the country you are in, but, if there aren't any SAG actors in your area, then it's moot to use the contract. 501 c 3 is about your tax status as an entity. It has nothing to about conduct of crew and cast during production. The only message that 501 c 3 sends is "Hey, we're a non-profit." It doesn't tell you anything about the behavior of people during production.