According to point 4, paragraph 12.060, of the Nevada State Gaming Control Board's Regulation 12, governing chips and tokens, "A licensee shall not accept chips or tokens as payment for any goods or services offered at the licensee's gaming establishment, with the exception of the specific use for which the chips or tokens were issued, and shall not give the chips or tokens as change in any other transaction." In other words, neither patrons nor the casino can use chips in lieu of money other than specifically at the gaming tables.
The same regulation states that, "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." That is, chips are only a symbolic representation of the actual money you cash in for and win; they don't belong to you and are therefore not yours to give away as tips or to use in the gift shop or anywhere else.
Of course, we've all seen it happen, or done it ourselves, so we put in a call to Gaming Control for the final official word on this. Here's what they said. "It is actually a violation of the Regulations and of federal mint laws. Gaming chips are to be used for the purposes of gaming only. And, yep, drinks are frequently purchased with gaming chips, as are other items, but they shouldn’t be."
So yes, it’s a breaking of the rules, not to mention the law, but when compared to the other violations that the powers that be are concerned with -- cheating, stealing, underage gambling, counterfeit currency passing, etc. -- this particular infraction doesn't register too high on their radar.