I'd never heard of such things till reading these threads.
What about this one... supporting your stem while flowering helps grow fatter buds... oh, that one works.
What about growing with water as a medium... aquaponics.
LED's?
Slightly stressing the plants a few days before harvest helps create more resin.
My point is that we need to experiment... obviously, as mogie said, common sense must play a large part in any decisions you make. Driving a nail through a stem doesn't make much sense to me, so I'd never do it.