bicycle anti-vehicle defense mechanism

in other postings I have seen the term "car-dooring"- in Toronto we call it the "door prize" but all over the world there are drivers who stop or park in bike lanes and force us out into the middle of the road. Bike couriers have developed mad skills of horking (expelling phlegm at high velocity) onto the windshields of offenders, but others are too reserved (or afraid of retaliation) for this. For those I propose:

Mount a can of dayglo orange permanent spray paint on the rear wheel of your bike, perhaps camoflaged in a pannier. connect a cable, much like a cable release for a camera, that when the other end is pressed at the handlebars causes the spray paint valve to be pressed and a stripe is painted on the side of the offending vehicle.

It is unlikely that you will be seen doing this and the driver will receive an indelible lesson that they should not endanger bicyclists by parking in the bike lane.