Yeah, the kill switch is a really good idea for you civic owners. I was going to do it on mine (inside the center consol next to the shifter so you could only get to it through the shift boot.) The MINI comes with a code jumping immobaliser with it's own battery and the whole system is neatly packed into the frame rails, it's one of the least stolen cars in the US.

 

kill switches work pretty well but even still i'd prolly get some kindof an alarm. if its just that much harder or attracts that much more attention then the thieves arnt gena take the risk and look for an easier target(if their smart enough that is..)

 

your not supposed to tell people where its at

 

If you want to have some simple fun in the spirit of the top post, you could run a NO/NC switch. The NO connecting the ignition to the ignition switch and the NC connecting a relay that stays on until you switch it off. (whether or not the guy lets off the ignition switch) The relay would in turn sound the horn.

This way, the thief has no idea the car is ghettoed until he already has the horn going and doesn't know how to stop it