What stops people stealing artic trailers?

[sunbeam alpine]

Sister-in-law is in hospital just now (fortunately nothing too serious) and we visited yesterday afternoon.

When we left the motorway on the way to visit her, there were at least 20 artic trailers parked up along the side of the road, with room to reverse the tractor unit in and hitch up.

It made me wonder whether there is any kind of security, or whether any lorry could just hitch up and head off. Or maybe they're not attractive to thieves? (assuming they're empty).

[sunbeam alpine]

sherman said:

I assume the one parked up at the roadside are empty and waiting on a load. Free parking rather than taking up space in a yard.

I think they're just parked up at the weekend. I go that way a couple of times a month during the day and have never seen them.