I find it very funny, how these double spenders make a brand new Bitcointalk account and complain how they weren't paid.
They also should realize that unless they use a completely new wallet, its very easy to track a given wallet just by looking at the change addresses. Just because your bet comes from a new bitcoin address, doesn't mean there isn't a trail with your other previously used addresses.
That's why I find it pretty surprisingly why they even bother going on those forum and complaining after they got caught trying to steal.
Don't have proof to show they are deliberate double spenders, but the rule of decline payment to low rank members is a bit unreasonable and illogical.