I know an old grower who has had the same stuff going for 20-30yrs, all from seed. He only grows one or two BIG outdoors a year, there is always a couple of seeds (only a couple) out of multiple pounds and these are the seeds he uses next year and I have never seen any variation over the 15yrs I've known him. He never gets a male and you would hardly call these beasts much of a herm, but they are technically fem seeds from self pollinated hermies.
Much of the connoiseur stuff of today was started from bagseed found in weed from mexico, colombia, afghanistan, etc. While some would have been regs, even a dirt poor, unneducated third world farmer knows it is not good to have males spoil his whole crop, so most were probably fem/herm seed. Old journals some of those guys left say how much breeding was required to remove those herm traits in early stock.
I think it is just another amazing way this plant can reproduce and like anything, if used/manipulated well with a proper understanding, it has it's uses. I have never had any problem/difference with good fems. Just growing sensi is manipulating the plant's breeding cycle to suit us, not it.