I did it last summer. Was going to Europe for vacation, and time got away from me leading up to leaving. Wasn't intentional that I left it, but I basically shut things down and forgot about the plant until I came back a couple weeks later.
As far as potency, I didn't really notice any change from when I shut down to when I actually harvested, but it was a bit of a mess harvesting. I very much would rather take all the fan leaves off while it's still moist enough to just snap em off. Also in doing this, the buds/plant were much drier than I would normally like prior to curing, so it tasted a bit of grass instead of smoove goodness.
Personally, I'm not a fan of the dark period at the end of flowering. Not very many of the people who talk about it have actual lab evidence to back things up, they just have their opinions... I believe 2 (or however many) days of extra light is more beneficial to producing more potency than 2 days without it. Course I also have no lab results to back up my theory either.
What I do to let the plants know it's last chance to do their thing is to start dropping temps a bit the last couple weeks. I also usually heat my water to 70 or so degrees so the plant uses less energy to heat the water before it can use it. During these last couple weeks, I will stop heating the water, and leave it around 50 or so degrees to mimic the cold rains of autumn. This seems to bring more color and more stink for me than trying to make something happen in last few days, as I think it takes a bit longer than that for the plant to react.
Your final flush should be the only starving you do to your plants i think.
