Why Are These Bills Sticking Together?

Woman: Sorry, I have to pay in singles.
Cashier: That's okay, people do all the time. (asking innocently) Are you a waitress?
Woman: No, honey. My career is a little less wholesome than that.
Cashier: (stutters and looks at her screen) Alright then, your total is $27.45.

Kroger
Cincinnati, Ohio