Agreed
This is stealing and the behavior of the owners/operators is outrageous, in my opinion. That policy is completely unjustifiable and I hope nobody uses this site until it's changed.
On the other hand the BitBet operators are strictly following contracts between themselves, shareholders, and bettors.
The action that creates a valid Bitcoin transaction is called a signature for a reason. In this case snackman signed a transaction to a recipient who had already GPG signed a contract with shareholders describing exactly how this situation would be handled.