You've probably experienced this by now in this day and age: A cashier holding your $100, $50 or even $20 dollar bill to a marker or a light to help with authenticity.  I'm okay with it, they're just doing their job, but it doesn't always work. Some older bills just don't react to those markers.  That's why a guy in Tennessee was falsely arrested when a conveinence store clerk called the police to report somebody trying to pass a fake $50. It wasn't fake. Police apologized and I guess the guy was cool about it, shaken but not too angry.  I was questioned about a $100 bill I wanted to use to make some purchases recently. I told the clerk, "What, you've never seen Ben Franklin wearing a ball cap backwards?" DB