Technically speaking so are the RFID scanners beside the exits to a store and plenty of stores still keep them in place. Ive seen cellphones set them off, items from other stores set them off, improperly scanned items set them off due to the tag not being deactivated... the list goes on and on.

Besides my initial idea was meant not to deter the shoplifters but to keep track of the amount of RFID tags entering and leaving a bathroom in order to help loss prevention.

For example: Let's say that LP John is watching suspicious customer Susie and that LP Jane is monitoring the store's security feed. LP John watches susie throw a dress into her purse as she continues to shop at the store. LP John follows Susie to the bathroom entrance but goes no farther. A camera pointed in the general location notices this. Susie is the only customer to walk through the female bathroom entrance within a specific time period. As she passes through scanners pick up 9 active RFID tags on her person. LP Jane takes note of this. As Susie leaves the bathroom LP Jane notices that this time the scanner only picked up 8 RFID tags. LP Jane notifies both LP John and a member of maintenance that and RFID tag was left in the bathroom. LP John proceeds to follow her while a member of maintenance collects the trash and inspects the bathroom. Maintnenance discovers a detatched RFID tag in the trash alongside a detatched UPC code. Maintenance informs Jane who informs John. John stops Susie as she leaves the building and last Point of Sale. John asks Susie where she put the dress. The usual loss prevention shit happens and Susie winds up in a small room where she reveals that she stole a dress by removing the RFID tag in the bathroom. The video evidence along with the observational evidence made via the RFID scanner can now be used in court to convict Susie of shoplifting the dress.