Years ago the recording industry released what were called "records." When a record company sells a record, it pays a royalty to the artist. When the record company gives away promotional copies, the artist does not get a royalty.

Record company representatives used to visit deejays and radio stations. If the radio station needed a copy of a new record, the rep would give them a box of them - knowing full well the deejays would set up tables at record shows and resell those free promo copies for substantial sums of money. Everyone knew those deejays weren't reporting the income.

It was a crime - tax evasion. It is also unlawful to stiff a recording artist on their royalties under both contract law and federal law.

Some crimes go unreported. Some businesses operate on the shadier side of the street or decide to make people happy at little cost. If the record company in my example, or the casinos in your example, wish to crack down, they have that power. I make no judgment about what are essentially minor economic offenses, and businesses often turn their heads. It would be foolish, though, to jump on a soapbox in front of the executives and demand that they watch (and allow) what you're doing.