Chargebacks. More than likely they will not see it back. Basically someone deposits 2K, loses it, and then withdraws the money from their bank account before it clears.
FullTilt can't recoup it because it is spread out amongst several other accounts that won the money and then it spreads out again.
Of course they could pursue the player, but being an offshore gaming site, no U.S. banks are going to be that keen to help them. Likewise I doubt it's worth the risk for
FT.
Most people that intentionally chargeback are scammers and will not attempt to repay the debt.
Chargebacks suck, but it's all part of the business. They suck even worse for the operators.