My parents neighbourhood watch had an article in it by the village bobby (who was then living in the vilage police house before it was closed and sold off). He was suggesting plants to grow to deter the burglar. The one I like, but can't remember the name of, was a thorn bush, tree or climber that had prominent thorns (could be a type of euphorbia) that once it scratched someone it forms nasty red weals that take ages to heal and disappear. Apparently a lot of burglaries are carried out by known offenders, especially up in semi rural areas like our. That means the police can just keep an eye out for the first one of them with those red weals and arrest them. Kind of a deterrent and a security marking.
I know someone who put thorn branches on top a fence to deter cats. It worked, kind of, the cats still walked along the fence but kept putting their paw down and picking it up quick when they hit another thorn. Eventually they get so far and give up after a lot of pricks.
We have tow sections split by a pedestrian walkway. One side has one gate which is padlocked the other has a padlocked gate one side and the other is a small wooden double gate with only a catch latch on one side and a ground bolt on the other. So it is secure with a chainlink fence about 1.4m high around 3 sides with a steel frames gate with the same chainlnk in it and oneof those square openings around the slide bar bolt which is locked with a padlock. The padlock is always jamming up so I just use the other gate and don't need a key. We don't really have any problems with theft I think. Probably something to do with a lot of houses overlooking it with a lot of people elderly in nature walking past it during the day. Plus some retired people with plots who tend to be there a lot and the commitee member who lives overlooking it. aGood site even if it doesn't have a water supply.