Stem Piercing?

I was looking up advanced grow techniques on youtube and came across this guy who pierces the main stem in the last 2 weeks before harvest to stress the plant making tricking it into thinking it is under attack increasing resin production. Anyone heard of this technique? I'm interested to see if anyone uses this technique and what they think of the results.
heres a link to the video - Advanced Grow Tips 2 : Stem Piercing - YouTube

try-ed it all it seems with minimal results and lots of work, now i just turn down the temp to trigger increased trichome growth and ripening while reducing vegetable matter.