Eli5: how do anti theft radio frequency tags know i bought an item

Question

for context i just bought 3 bags of beef jerky from 5 below and they all had one of those square tags with the lines on them and i only scanned one 3 times at the self checkout how do they get deactivated

Edit [https://imgur.com/a/c3DFJFg](https://imgur.com/a/c3DFJFg) here’s a picture of it

In: Other

Answer 1

They may not have been anti theft tags. They may have been inventory tracking tags.

Or if they really are RFID, the detector may have sufficient intelligence to compare what just passed thru with what was just bought in the last couple of minutes and assume if three bags of beef jerky were just bought and three bags just passed thru the detector, they are likely the same bags so don’t alert anyone.

Or, if those bags were placed on the counter they may have been deactivated even if you only scanned one of them.

Or the employees got sick of hearing the alarm go off and either turned off the detectors at the door or deactivated all the tags in the store. Sometimes stores turn off the detectors because they don’t want to hear the alarm and simply having them there doing security theater is enough to greatly reduce theft.