Relay and Neutral safety switch Question.

All good points, mine is an auto, will be wiring in a few relays, try to start it wrong and horn will honk and starter wont crank.just a deterrent.key operated battery switch. Or a continous duty solenoid to cut the power. Many choices. Blasting caps in the seat cushion would be effective but messy.
Wire aux ign coil under seat, and a plug wire in the gap,also a deterrent.
Thought about a cattle fencer too, remote controlled and tied to dome light.