This answer differs from person to person based on personality, If it is a greedy human...they may choose to quickly fire this casino worker, but if you consider that because of the relationship this worker has with this chronic gambler they have lost control and acted unprofessionally, you may just  scold them and caution against such unprofessional acts, but at the same time consider what caused her to act recklessly and try to add such a user to exclusion list so they have restricted access to your casino, maybe it can assist after all just his loss will not affect your profit.