So far we disagree that canceling not only winnings but a deposit as well is "shady" or "unethical", as Dre mentioned above this is to avoid the following scenario:
make a deposit
claim bonus
betting unsuccessful
cancel bonus
withdraw deposit
deposit is again
..and here we have a loop.
make a deposit
claim bonus
betting unsuccessful
cancel bonus
withdraw deposit
deposit is again
..and here we have a loop.
There is simple fix for this just change the rules and make the (original balance unlocked and have to be used first ) that way there will never be a loop and your site will lose nothing if someone canceled the bonus
.sounds interesting.