I'm surprised it locked up like that. About 15 years ago I was a frequent customer in a store that had these and I never encountered any problem with it, nor did I hear of anyone else encountering a malfunction while using them.

That store implemented those locks because they were the closest supermarket to a college campus. Some students were taking the carts back to their dorms and chaining them up to a tree with bicycle chains. They would also use those carts to go shopping in a nearby supermarket of another store chain.

Different continent though, so it's probably not entirely the same technology. People like reinventing the wheel.