What's the actual reason for BitBet to steal the coins in this situation ? "You're screwed", as it is written in the FAQ, is not a proper answer.
Explaining to users quite amply and repeatedly that going against sense and acting in a particularly risky manner is not wise and will not result in refunds, and acting accordingly, has nothing in common with stealing.
You still haven't explained the reason that Bitbet steals the coins - I only went "against sense" and acted in a "particularly risky manner" in the context of your site's
.