Car immobilizer at Narita airport

Before you can drive up to the airport terminal in Narita, you need to stop for a brief inspection to make sure you aren't carrying any bombs or other dangerous items into the airport. The officer typically asks to see some ID and then if it is okay to open the trunk. They do a brief inspection with a mirror to check for items underneath the car and then send you on your way.

What I noticed this time, though, was that after they let me go, my car's engine was off. The key was still in the ignition in the ON position, and the car was still in gear.

The only thing I can think is that they've installed a car immobilizer to kill each car as it passes through inspection. I suppose so that you wouldn't be able to get away if they did catch you with something.

I'm curious as to the possible detrimental impact of getting the circuits fried like this.