(...)This does not need to be in the terms and conditions because it is similar to if you had .01 cents in bonus left on your account. If you were to redeem $10 in bonus and then lose it all except of .01 cents, you would understand that the wagering requirement still applies. If you then redeemed a second bonus of $10 on top of this naturally the two bonuses would join together as you have redeemed a total bonus balance of $20 without ever having reset the wagering requirement. Losing the total balance of the bonus is the same thing. Just because you have lost the bonus it does not mean that the wagering requirement of that bonus has been erased.
This is the same in the event of a withdrawal while having a bonus balance:
8. If a Player makes a withdrawal, their bonus account is reset to zero; however any unmet wagering requirements will remain. This means that if a Player chooses to take back the money they deposited, they will lose any bonus money they may still have remaining in their Bonus Account.