My buddy has an 89 Prelude that got stolen a couple of times. It basically got driven around and left with an empty tank around town both times and no signs of break in. I think the keys are relatively common for those so maybe the thief has one.

Anyways, I installed a switch up under his dash the disconnects the fuel pump +12v wire. It takes just a moment to flick the switch if you know where it is, and afterwards, the engine will crank and crank and crank and sort of sound like it wants to start at first, but never do anything. It would probably take several minutes to find it if you had to look for the switch, especially if it were at night and you were trying to steal the car. Seems like a good lower tech deterrent to me! The car has not been stolen since.