A casino chip in a player's possesion immediatly becomes an "accounts payable" to the casino. Since it is highly unlikely that EVERY chip in the casino will end up in player's hands, there is not an obligation to have the equivalent cash on hand for the casino. However, a casino must pay cash for the chips presented unless there is a strong belief that the chips were obtained illegaly or by any other illegitimate means. The state of Nevada does mandate that enough cash is maintained to pay all slot jackpots if it at once. While this does not pertain to chips, there is a minimum bankroll requirement regulation that you can access on the GCB web site.
A few interesting tidbits on this subject were:
- Becky Behnion not paying Bob Stupak cash for his $5000 chips.
- Tom's in Henderson not having enough cash to pay a keno ticket.
- Ormsbey House in Carson City not having enough cash to pay a keno ticket.
- Also I witnessed a bar in Las Vegas not having enough cash to pay my friend, however, after suggeting we call Gaming, the cash arrived in about 30 minutes.

long story short, a casino will pay or they will most likely lose their license!