I’m not sold on that. I am probably engineer over-generalizing rn, but I can totally see hairs growing as a result of directional growth rate differences and localized fluidity changes caused by the presence of defects in polycrystalline zinc exposed to an electron current.

There could also be a resonance phenomenon caused by waves in the current moving around imperfections the metal.

Maybe the metal atoms undergoing electron drift are guided by electric fields through the air to areas of differing voltage, a self-fulfilling short circuit.

I’m going to guess the challenge lies in isolating and observing these effects to figure out precisely what is going on.