Question: what is the law regarding casino employees gambling at the casino they work at?

This week as I approached my partner playing at a VP machine, I noticed one of the pit people from that very casino playing right next to him. Ms 'Pit person' (who I deal with frequently) was obviously off duty as she had a drink in her hand. Upon noticing her, I did not acknowledge my partner, but just walked by, as I wanted to avoid an unnecessary association.

So, I am just curious as to the law? I was under the impression that employees could not gamble at their own property. Maybe that has been changed. Anyone know?