Don’t know the punishment, but I think I would get some of that cheap white wire fence from Walmart or the cheap plastic edging, and run that around the garden.
Put some of those wind wheels at the corners and midway on each side. That way the garden is clearly designated, so there can be no excuse for confusion.
It’s a 3’ wide strip surrounded by a wall on one side and cement on the other three sides so it’s obviously not part of the yard. In August, he mowed through the front flowerbed which is also bordered with cement and 5’ fence. He’s done this for over 20 years so I’m thinking spotlights, sirens, landmines, razor wire and guard towers with a take no prisoners policy.