In the past few years here retail and others were alerted to counterfeit bills not only the larger ones. We had a good bill to compare with the counterfeit ones..which was easy as the cash register had these in there anyways. Here a few years ago high school students photocopied money ( $20 bills) using the High Schools new photocopier/printer that copied perfectly. After passing them undetected throughout this Town and major City nearby they finally got caught! The insurance of each Business covered the losses. But the kids ( under age 17 yrs old) had a Federal agent warn them that they could had spent years in jail, and they were let off with a stern warning and probation…and possible record of that for life.( some had this record purged when they reached age of majority ( 18Yrs). Since then, Business have a device to check bills under an ultraviolet ray device. Apparently travelling salesmen every Fall tried to scam this Town and others with phony money but it has been curtailed as Businesses are on the alert now. Also we never took any $100 , $50, bills as it depleted our cash reserve for the day. Most use credit or debt cards now.