Although they are unlikely to be enforced.

Just remember - you cant buy the chips. Casinos cant sell you the chips. They are IOU's. They are always the property of the casino.

I am not going to say I am a legal expert in this field but in my opinion they must be IOU's in every other state also so it should follow that all casinos can force you to cash your chips if they wish to, regardless of statutes outside NV.