how do the sensory machines at the doors of big shopping chains work? how do they know when someone is walking out of the store without paying for the certain object

Question

how do the sensory machines at the doors of big shopping chains work? how do they know when someone is walking out of the store without paying for the certain object

In: Technology

Answer 1

Oh I got you okay they have tags that send out high frequencies that the towers “hear” and it sets them off. Printed bar codes dont set them off unless they have an RFID inside (one that does).
Don’t steal?
A lot of the time they don’t know though, like if two people walk out they’ll assume it’s whoever stops in confusion