I always said I would put in a fence later.
A few options for you. I have a row of mango trees along a walking path behind my house that gets light foot traffic. I have trained and pruned those trees to remove the lower branches and put the fruit out of arm's reach. Yes, it's not the ideal way to prune the trees, and I need to pick them with a pole but that shuts down 99% of would be thieves.
You could install a cheap fence that's easily removed if it's in the wrong spot. Get a roll of cattle panel from Home Depot and some of the big green stakes you hammer into the ground. You could fence the entire front in an afternoon for a couple hundred bucks. Then grow passion fruit vine on or Seminole pumpkin on the fence.
I have been using Canna Lilies to establish borders and visual walls in the garden. Some Cannas are 8 feet tall and they can be planted in a row where they will spread and fill in the gaps to form a wall within about 2 seasons. Plus you get year round flowers. So think about a wall of Canna Lilies to visually and physically block fruit pirates.