The only thing that will actually work is some sort of intimidation, the thief knows to check again this season for pot, and they know they got away with it. Personally I would want to scare THAT thief, maybe a sign with a written "warning" saying youre ready or waiting or whatever. Sucks to have to have to post that on your property, but the fella is likely to return
Things like lights and fence may deter him enough, that wouldnt be enough for someone who has successfully stolen and will likely case the your place again. Gotta scare him
When all else fails, take all the groceries into the house in one trip, and do it all while grunting heavily and wearing flip flops. It will scare anyone watching like nothing else. Highly intimidating. Lol.
In all seriousness though, some beware of dog signs, preferably ones that say warning - not responsible for injury or death. Gives them something to think about. Plant thorny plants on both sides of the fence, all the way around if possible. Setup a multilayered detection system, with backup power incase of outage.
Scrogging plants makes it harder to pull them out of the ground when your net is really secure, and staking a few thorny branches around the stalks near end of harvest will give a little surprise to anyone trying to rip you off. I don't really consider it booby trappin cause it's natural, and you can always say it's how you deter rats from chewing up your stalks. Either way, if someone's on your property with bad intentions, they're already in the wrong. I've heard of people wrapping barbed wire around the stalk, but I wouldn't recommend anything extreme. Natural defenses can be extremely effective in deterring potential "pests" lol
Also, signs stating the property is monitored by video surveillance, incase they can't see the camera from their vantage point.
Avoid a set schedule, come and go at random. Keep your eyes OPEN, employ counter measures as well as counter surveillance and know the property around you very well. If someone so much as takes 1 step around your property, you should know. Study tracking and know the landscape around you. Take note of anything that seems out of place and monitor it. Set up hidden cameras. There may be a possibility of identifying who it is before they commit the crime, could potentially be someone you know.
If you can convince some close family members to grow too, it will help secure a harvest for everyone as well.
Hope this helps...