I've always felt it was a thing by genetic evolution, if a gene spent 20 years protecting itself from high light levels, it would likely have a stronger UV/IR defense mechanism for its offspring, like how people from equatorial areas have darker skin that carries over to their children even if they move.
Some genes don't spend this kind of time in a high UV environment, these are possibly the ones that would respond better to an addition of UV, its too bad i really got no clue as I've never tested this.
Ive got an abundance of equatorial beans but no time to pop them indoors lol.
trichomes are also used to help catch pollen & reduce harmful insects.