Could it be possible for someone to unknowingly pass a fake bill?
Say I use a hundred dollar bill to buy $36 worth of something somewhere. I get three twenties as part of the change. One is a counterfeit bill, but I don’t know it.
I then use it at another store the next day to buy something. Am I guilty of passing a bad bill?
I hope not, given that we all accept “change” and never check it. I don’t feel like carrying a pen around to mark every bill I receive.