When I was a supervisor I told my employees to refuse to answer personal questions. They don't need to know your religion, sexualty, relationship status, politics (etc) to buy something. If anyone gives you crap, you call me and I'll tell them to leave and never come back; that they were banned for harassing the staff.
And I did it.
The most memorable was a so called 'good' Christian who brought Robbie near to tears calling him a dirty faggot, how he was going to hell, etc. All because the guy asked Robbie where he got the necklace he was wearing (a cross even). Robbie said the name of a shop located in an area popular with the LGBT community.
So I come onto the scene like a ninja and in a very scary voice, pop up behind the guy and tell the religious freak that he needs to leave. The religious freak jumps a mile, then tries to bluster about how Robbie is filthy and that he (religious freak) demands the kid be removed from the premises, as his lifestyle was offensive. (Robbie isn't even gay, he just happened to buy the thing at a known LGBT friendly area).
I reiterate that the religious freak is no longer welcome in our store, and has two seconds to haul his bigoted ass out the door or I will trespass him off with cops. He storms out, threatening to call corporate.
Good luck with that, sir. I sent Robbie on break, and sent an email straight up the line detailing the incident.
Never heard about it.