I have well over 200 sites Cat, and yes, if a casino accumulates a large negative balance that they carry over I will go to all of those sites and remove them. This is a business and what I have to offer is real estate, if I am not being paid I have no choice but to remove the non producing casino and fill that real estate with casinos that do make me money.
Needless to say after being forced to do all that work I will be very reluctant to ever put them back up on all those sites. So in my case a casino would lose a major affiliate over what could be a nominal fee over the long term.
Negative carryovers are penny wise and pound foolish for casinos.