It is a good method of promotion used by casinos to attract more gamblers to play on their sites as the gamblers are still able to get some of their money back if they were to lose all of their initial deposit on their account. But I truly doubt that any gamblers would withdraw that small amount of money returned to them via the casinos rebate promotion, I guess almost all of the gamblers would just continue to wager with that money and hope that they are able to recoup all their losses.