I know gamblers behave like children sometimes; I would know, I'm a dealer, but that doesn't make them a child care facility per NRS 202.265.
NRS 202.265 Possession of dangerous weapon on property or in vehicle of school or child care facility; penalty; exceptions.
Oh how I wish it had been me in your shoes! As the primary campus carry advocate in southern Nevada I would have called them out on their BS immediately. I would have embarrassed them until they informed me that I was being asked to leave or face a trespass complaint.
Remember, when arrogant, ignorant, douchbag, wanna be metro washouts known as casino security tell you that they do not allow firearms, THIS IS NOT THE SAME AS BEING ASKED TO LEAVE! Also, expect to be assaulted by them, so have your recorder running,
you too could win $250,000!