Working in a casino is no different than working in anyother service industry job. You tend to be paid minimum wage and like other service industry jobs the remainder of your salary comes from gratuities. The simple rule is if your dealer is being courteous and helpful you tip the dealer. You are under no obligation to and if you do don't expect the dealer to bend the rules for you. No matter how big your tip is they are not nor should they be expected
to risk their job for you. Consider a tip to the dealer as a donation to "Lady Luck" and maybe you will experience some good Karma for your action.