The Culver's in Winnebago caught a fake $20 after being duped weeks ago. 

The bill in question looked like a normal twenty dollar bill but had "For motion picture use" printed on it. Apparently, at a quick glance, it's hard to spot.

MyStateline - Chief Stockburger says to avoid being duped, check for a water mark by putting the bill up against the light - paying attention to how the money feels and making sure to take an extra moment to read the words on the money. And, if you have one handy, use a counterfeit detector pen.

The moral of the story is that if you're dealing with cash, especially now, it would be a good idea to take some extra caution.