A colleague had a more dramatic anti-tailgate technique. This was eons ago, back when some vehicles had a manual choke for cold starts and no pollution control features. Poindexter installed and wired a spark plug near the end of the tailpipe.
When a tailgater rolled up on him, he pulled the choke out for 10-15 seconds – letting fuel mix and exhaust get a bit rich. Then toggled the switch he’d installed on the dash, triggering the spark plug. The resulting ball of flame exiting the tailpipe generally did the trick.
