Here's what happened to me:

I was putting in the code to the jetway door and some woman said, "Where have you been? The bar?"

I said, "Come with me," and walked her over to the CSA.

"This woman has just made a public accusation that I've been drinking. Unless you want me to delay this flight for two hours while I get an alcohol test, you might want to explain to her why that was inappropriate."

Then I went about my business.