Hello there. I heard this as well and I actually did do it in my first grow, but only for 48 hours instead of 72 (didn't want to push my luck, just in case). It worked! They did noticeably swell and there was one last trichome push when it was all said and done. It's also recommend that you drop RH and temperatures too, if you're to do this. It's essentially extra stress and confusion which pushes her into panic mode and she will try one last desperate attempt to push and catch pollen, before her cycle is officially over. I have heard of some people doing 96 hour lights out at harvest, but IDK, that seems a little risky. Prolonged wonky lighting schedules can cause self-seeding and I wouldn't want to risk that. But with 48-72 hours, from what I've read, even if she tries, there's not enough time for seeds to develop, so you're good. I guess what I'm saying is, it's worth a shot and it can't hurt. Take a bunch of 'before' pictures and then your 'after' pictures to see if there is a noticeable difference in size, trichs and swell. Best way to go about this is to try and see what happens. Again, it won't hurt them, so why not? Plus, there are many, many veteran growers that vouches for this technique.
Go for it!!! And good luck with your harvest! Great job and congrats man! Chalk another win up on the board!😃👌