Theft is a major problem for hotels who accept cash. Counterfeit money is getting much more difficult to distinguesh in today's world. Simply putting $100 bill toward a light is not the answer anymore. Hotels lose thousands of dollars annually on $20, $50 or $100 fraudulent bills. That's why you need to have a counterfeit detectors at your front desk that prevent "bogus bills" being passed and protect yourself against this type of theft.
LodgeMart.com offers some excellent counterfeit detection devices which are very affordable yet will help protect you from losing hundreds or thousands of dollars.