I thought of this back when I was 8 and mowing my parent's yard. I also imagined a laser powerful enough to simply swipe once across the yard and cut down the tall grass. That damned tree was an impediment to my desires and frankly, a pain in the ass to mow around. Decades later I retaliated and bought my dad a beautiful tree to plant in his front yard and then HE had to mow around it.
I live in the very nicest part of metroparkentralis but even here if one leaves a bike or a car unlocked for more than a minute some miscreant will swipe it before you can say vibrant. I could see buying this mower if it came with the self detonating package for when it gets picked up. It should have at least a pound of high explosive and some forged shrapnel would be nice. I'd settle for a killing electrocution system and I remember about low voltage DC fire control systems that would allow one to sizzle for hours unable to let go. On the gripping hand, we have the local elementary school right across the street so maybe not....
I am always mindful of what I read once decades ago in the SURFPAC EIB that described the death of a young sailor who touched the casing of a fire pump in the engine room. As it happened, it turned out that some electrician had been working on the wiring for that pump some hours earlier and made an error putting it back together. Because of his negligence the full current for the pump flowed to the entire casing which was about 400 volts.
Sadly, the law everywhere frowns on booby traps.