Hussar
Legend
No. You can't copyright game rules. But you can sign a contract which says you won't copy them.
I'm thinking that that would be HUGELY unenforceable though. What are the odds that an entire group of players would download the rules, instead of just a couple? Would the agreement include a clause not to play with anyone who hasn't signed the agreement? I really don't think so.
This is an open playtest. It would be very odd to have anything like that in something like this.