My grocery store recently added these locks on the cart wheels, I’m not really sure how they work since i’ve only ran into them once so far but it went off as I was going through the detectors at the door and locked up the wheels so it wouldn’t roll. Idk what triggered it because I went through the manned checkout and they scanned everything. The girl at the self checkouts just ran over and unlocked it without even checking anything. It was pretty embarrassing though because it was busy and I was blocking the exit door with a bunch of people behind me for like 30 seconds because of that.