I talked to the cashier about what went down and she said, "Oh gosh, you imitate him so well. I'm getting the manager."
I talked to the manager who seemed not all that concerned. At that point, I wanted to move on from the whole thing. I just said, "You know, this is your problem, not mine. I hope you deal with it, but it's really not my concern." And out I flounced. With the headphones. Which may have dampened the strength of my argument. But I don't care. I do what I want.