I found a lock very similar to yours. This one "protects" a shortcut between two public roads. So far so good - it's a reasonable security shrouded padlock with a heavy chain. This is also a "J" keyway. Their precious shortcut should be protected against casuals.

There could be implementation issues with the way this gate is locked though....
There used to be a vehicle trap at this location, which seemed to be a beemer magnet. I saw vehicles trapped there a couple of times, and I suspect their cars might need an alignment. I actually though it was better as a vehicle trap, since the fire department trucks could go through, and they might reasonably be in a hurry to get through there. Spot the problem with this setup... you can't make this up.
