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

All of the bags have the same bar code, so scanning any specific bag should not matter or cause one to be deactivated and another not to be. As far as I am aware, none of the RFID tags can tell when you have purchased the good, they are just supposed to be removed before you exit the store, and if you leave the store with them they set off the alarm. 

Honestly at 5 Below they might just have put fake security tags on the beef jerky.