I've been going to my local for 5 years and know the staff by name, I see the same security nearly every time.
After leaving scan as you shop and exiting the store, my trolley stopped past the security beep things and wouldn't move, as if it was frozen on the ground! Security marches over and wants to see a receipt despite the alarms not going off and has this weird device in his hand that said 'trolley lock'
Wtf is that?! Baffled why I was stopped too but that's not my concern here as I know they have to do regular stops.