Got an answer from them a few weeks ago and forgot to post it here:
The $5 is actually in the player’s account, but the minimun buy in is $10. They will need to deposit an additional $5 in order to play. We don’t allow players to withdraw until they deposit as an age verification tool. Otherwise players will be able to join free rolls and play and withdraw and be under 18. Depositing is a way to make sure they are over 18.
When I asked where it states these terms I never got an answer. They’ll be our next pulled room, cleaning house lately!