This may be easier*than*you*think
Two words.
Stun Guns.
Ebed fine metal points into whatever are the key locations for someone to touch. (Handle bars, Ignition housing, seat), take the outer plastic shell off of the stun guns, wire the trigger switch to an electronic lock located in an obscure location.(dont lose the key) run the stun gun "stun points" to the wires leading to the metal points.
Locked = trigger depressed. Get close enough and you'll complete the circuit.
Unlocked = safe to ride..wysiwyg { background-attachment: scroll; background-repeat: repeat; background-position: 0% 0%; background-color: #324259; background-image: none; color: #e0e0f6; font-family: Verdana, Arial, Arial; font-style: normal; font-variant: normal; font-weight: 400; font-size: 10pt; line-height: normal } p { margin: 0px; }