There are a ton of laws preventing this behavior by venues. Basically if you sell tickets to the public, you HAVE to let the ticket holders in, barring bad behavior at the gate or contraband. The idea that something is private means you can do whatever you want is very naive.
> if she doesn't like this policy she can start her own Christmas Spectacular show.
She can also just sue and demand hearings about licenses that further prevent this kind of behavior (i.e. public venue, hospitality, zoning, liquor, food and beverage, etc...). From a social/business standpoint, punishing lawyers for working for an opposing firm is very small minded.
Also facial recognition telling gate agents who a member of the public works for is scummy.