The Nevada casinos probably handle more currency received directly from the public than most any other retail business. I agree, but banks and casinos were the focus of my question not retail stores. Since they don't examine currency AT ALL at the time they take it in, I suggest the anti-counterfeiting measures are irrelevant to them. As JimK pointed out, they may detect them later hours or days after receipt but too late to prevent a loss. REREAD Jim K's post. He pointed out they DO check at the point it is taken in you missed the part about the 'feel' of the currency and how the dealers handle so much it is hard to pass a bad bill to them. They may get them out of circulation, but they still eat the loss and the counterfeiter makes a profit. My question asked nothing about who eats the loss or who makes a profit, only how many are discovered and what denominations.

This assumes they are infrequent small transactions. I assumed nothing- I asked a question. I have no doubt that if you passed $100,000 in counterfeit currency, the casino would be looking at security tapes and the Secret Service would come looking for you [g]. I agree. But I also believe the ALL counterfeiting is taken seriously. The greater the number of notes the more effort is put on finding the source. As someone else pointed out in the thread, many counterfeits are passed by people who received them and have no idea they are passing one. So even a picture of a person passing a fake may not land him in jail – they just may be asked a LOT of question though –

UNRELATED TO MY QUESTION:
My son working at a restaurant during college picked up a fake $20 and it was discovered after the people left, HE had to pay the $20. Then he asked if he could have the note (for my collection) and offered to buy it for another $20 but they refused. He ate the loss.