I dont see how it can ever be enforced. I think it is an attempted reinforcement of the fact the board doesn't like collectors (and actually loathes them). I was told that this rule is not a new one. It was claimed it is implicit in the following (Nevada gaming regs extracts):

12.010 Definitions. As used in this regulation:
2. “Chip” means a non-metal or partly metal representative of value issued by a licensee for use at table games or counter games at the licensee’s gaming establishment.

12.060 Use of chips and tokens.
1. Chips and tokens are solely representatives of value which evidence a debt owed to their custodian by the licensee that issued them and are not the property of anyone other than that licensee.
2. A licensee that uses chips or tokens at its gaming establishment shall:
(c) Promptly redeem its own chips and tokens from its patrons by cash or check drawn on an account of the licensee;
(d) Post conspicuous signs at its establishment notifying patrons that federal law prohibits the use of the licensee’s tokens, that state law prohibits the use of the licensee’s chips, outside the establishment for any monetary purpose whatever, and that the chips and tokens issued by the licensee are the property of the licensee, only;