Well, in my case, based on past associations - but given that a place of business pretty much has complete authority to ban whoever - they don't have to know - they only have to suspect - in fact, they even don't have to suspect it. It doesn't have to be reasonable. They can ban me for driving a Toyota if they wanted to.
I was thinking that since they are hindering the livilhood of a third party, CA would take a dim view on the anti-competition aspect of that. (Typically in CA, non-compete clauses are no enforceable)
Of course, they would probably ban me for just posting this
It is a sports facility, they only one of it's kind in the area.