I cringe when I see people suggest that a flush doesn't matter. I know I've just opened up a big can of flame-on here but so be it...
I partially agree with Antman15, and partially disagree. I however identifying that he has years of experience. More than me so Im not pretending to know it all, but here is "my" opinion.
If you don't have a choice then absolutely cut, cure, medicate. But just because something burns grey doesn't mean that it is clean. That misinformation can be dangerous when interpreted by the wrong, less experienced growers. Again there's a thousand variables so don't hang me right yet.. That's like saying that because you can't see mold spores on something that they aren't there and the product is safe. Product testing for some is about a pissing contest to see whose THC is higher. For some an intolerance to a pesticide, or an excess of a mineral could have a sever health impact.
Absolutely we have all smoked some shit that burns black and has to be re-lit. That also comes from some strains that have not been cured, that quite possibly aren't dry enough, is premature, or perhaps is a genetic disposition. I've talked to a few people who have experienced outdoor strains that even when finished on time, and cured, don't smoke worth a fuck. Most likely due to someone's experiments in breeding.
I had a full plot of outdoor organic kush that didn't quite finish because of the elevation and latitude we are at here. No chems. No additives. Just straight up compost, and a few organic time released ferts. Again nothing is "100% Organic" but as close as we could get. Anywho, the shit was dried and wouldn't burn worth a fuck. Threw 10+ pounds of it into rubbermaids and voila, with each 2-3 days the shit got better. Infact so much so that after 3 weeks that shit had ash like a cig.
I have also smoked shit that was growing in Promix that burned amazing. Looked great, tasted great, yet had zero flush. These clowns were also banging off PPM's above 1500 up to the very end. Don't try to tell me that because it burned good that the weed was safe.
There is a balance as well. Do I believe in a 2 week flush? not really. But again, it depends on the medium, method, and nutrients. if your only out there feeding them once a week then chances are they are consuming a large portion of the nutes in their system so no need for a huge flush compared to someone whose feeding quad digit PPM's EOD.
opinions are like assholes so they say... I'm no different.