I think this is cool! It reminds me of how Ferrari did a very similar thing with the dabs of yellow paint they used to mark bolts that had to withstand intense vibration:
That's standard operating procedure in a whole lot of industries where proper torque is mission critical. If you ever find yourself near high precision manufacturing or industrial lifting equipment (think hooks and lifting eyes where a crane picks a load up) you can't miss the torque marks on bolt heads and/or nuts.
Same deal with GM restoration judging. Judges at Bloomington Gold will get very specific about the bolts used on a car, but a panel was held with a retired GM factory employee who put together first or second-gen Corvettes, and he said something similar: Sometimes they ran out of bolts at the factory, and when they did somebody would run down to the local hardware outlet and just buy whatever bolts fit the spec.
This kind of thing is done in aviation, and the stuff is called Torque Seal or Inspection Lacquer. You tighten the nut to the proper torque, and put a dab of lacquer across the thread and nut. Whenever you inspect the part later, if you see the seal broken or mis-aligned, you know the part has vibrated out of spec, and need to replace and re-torque the bolt.
http://www.tomyang.net/cars/story1.htm