I think it is a ridiculous idea to stress your plants for an extended period of darkness right before harvest.
Harvest asap would be my advice, before she freaks out any further.
Extended darkness will mess with the plants metabolism and I can't see how stressing a plants metabolism for 2-3 days after weeks/months of careful growing could be of any sort of benefit and the whole idea of doing this is an urban myth created by someone too high to understand how plants grow and function. Stressing plants right before harvest would have to be one of the worst ideas ever.
I would much prefer to have my plants functioning happily and normally right before harvest and not be freaked out.
After much experimenting over the last 3 decades, I believe the best time to harvest is about 2 hours after lights on or the sun comes up, without any metabolism destroying techniques such as a freaky extended dark period. I can not find any scientific evidence as to why this technique would be beneficial or helpful in creating superior flowers in any way, and is as I said earlier, truly an urban myth.
Hope this helps,........
Organoman.