No — not at Casino Rewards.
With the wager share model, you are paid based on the amount wagered. If the player wins more than they deposit, this is actually a good thing for you (assuming you are on the wager share model like most people), because now they have more money to wager than they did to begin with. It is impossible to have a negative balance with this plan, unless you get a chargeback.
If you are seeing a negative balance in your stats, then you either (1) had a chargeback, or (2) you opted to remain in the revenue share model instead of switching to the wager share model.