I like Tony's rotor idea
A couple decades back, I had a 260. It looked far nicer than it actually was. I'm tall, so the seat was always in the most rearward position. I lived in an apt. complex in a not-so-nice area. One evening, someone stole it, parked it under a bridge, and took the wheels and stereo. It was recovered the next day, with the seat *very* forward. Once back in my possession, with fresh equipment, I would swap the coil wire with one spark plug wire (at the cap). I reasoned, in the dark, the chances of the average Datsun thief figuring this out would be slim. A few mornings later, I found the door unlocked and the seat *far* forward. I'm reasonably certain it was the same pond scum. It worked at the time. And depending on the level of thief you're dealing with, it may work again.