[wilbilt]

Saw a setup years ago with a pushbutton momentary switch mounted in the cig lighter socket. Pushing the lighter in or pulling it out would open/close the switch contacts.

Depending on what type of switch used, NO or NC, you could have it enable/disable the ignition, cranking circuit, fuel pump, or take a picture of the bad guy, release the hounds, etc.

Since most people don't smoke these days, the lighter can be used for a higher purpose.