Hey, the contest is over! (although I'll read with interest what LoyceV sent).
Rollover or wagering requirements. Most casinos require that the amount you deposit be wagered/rolled over 1x, 1.5x, 2x times, etc., before you can withdraw your coins. It's intended to prevent abuse and not have players use the casino as a mixer or worse (a front for money laundering).
I don't know if this will be implemented in the future but there are no wagering requirements at this stage.