Do what I do.
Get yourself a body cam on Amazon (they aren’t terribly expensive) and have it turned-on and with you when you go into these places.
Then when approached by a Mask Karen tell them about your cam and that they are live in the World Wide Web right now. Ask them for their name and where they work.
You’ll see them run away as if you’d just lit a stick of dynamite.
haha i love it