Clever anit-theft switches

Whenever I'm in a shadier neighborhood I just pull the wire from the coil to the distributor. But on my other car I have a discrete fuel pump toggle relay. Sometimes I like to imagine a thief taking it, starting it up, starting to drive away until the float bowls run dry, and then walking 400 feet up the street to ask him what he's doin. :D

But as far as doing a cigarette lighter kill switch - you could get a On/Off switch like this

40-1672-02 Judco Manufacturing Inc. | Switches | DigiKey

and mount it inside the hole of the cigarette lighter with a "dummy" lighter plug to press it (although this makes the lighter useless...)