Plumbers & dish towels

I had made an appointment to have a plumber come to my house yesterday while I was at work. The night before, I stood at the kitchen sink & looked at my nice, brighter-and-cleaner-than-most dish towel and thought, "I should hide this. One other time when a plumber came her, he used my dish towel for some part of his job, & left it filthy." But, I didn't take my own advice. I left it there.

Yesterday when I got home from work, the dish towel was gone. But he had left me a filthy rag. LOL. I can't figure whether he switched them w/o realizing it, or whether plumbers in general (or men in general) just think it's OK to use/take a stranger's dish towel...

Ever run into anything like this?