Well I think there are two types of female seeds to be honest. And I have a feeling that a lot of the seed breeders out there are selling feminized seeds that are actually just selfed or hermied seeds.
I'll try and explain myself as simple as possible. Take the DOG for example, although not really an accident, the seeds have come from a Headband that tends to throw out male sacks (a herm trait basically) and they have been used to germinate a number of OG Kush buds. So we have a plant with a particular genetic make up pollinating another plant with a different genetic make up. Now without going into whether or not the plants have similarities in there genetic make up, you are going to get a set of resulting seeds that produce some plants with no herm trains at all, or very little, some with a little bit of herm, and some that will basically look like males, but will also have some female traits. Most of the plants are going to be females though and then when grown indoors, will produce some male flowers (like the plant you have grown.)
Now as a lot of us on here do, pull them off, pinch or tweak with tweasers, and move on. If a flower has opened I doubt your whole crop will be ruined, probably just the buds around the flower.
Then you get the method of creating fem using collodial silver, now although this is something that I am planning on doing soon, I cannot claim to have any experience in producing these type of female seeds. I can say that most of the females seeds I have bought have been okay and not hermied.
I will tell you one thing though, and I don't want to start saying this breader is that or that, but a lot of the weed that I have bought over the last 10 years has come from the Grey Area and a lot of that weed has come from DNA, and I can tell you a lot of it has immature seeds, or just plain good old matured seeds, which is where I got my Headband and OG Kush from many moons ago.
So take from that what you will, fem seeds are cool for what they are meant for for sure and I would def buy them again if I could get my hands on a strain that was excellent and only available in the form.
Any further Q's, just ask my man.
DST
@DST what have you got to say regarding female seeds turning to hermies