It will Beep. There is a small chip on it, a so called RFID Chip, which stores just a small amount of data, the state I was paid or I was not paid. When the product is scanned, the state on the chip is changed. When the state of a product is I was not paid, the System goes BEEP. Other possibility with the RFID Chips, they only have the state I was not paid and when scanned they get a small electric charge and are therefore destroyed. So the System only BEEPs, if there is a Signal, not which signal.