Actually, they do have a barrel of immature and shit seeds along with some good ones. All but one of the feminized seeds I have bought over the years, White Rhino, did not make it to harvest, about only 50% of the free seeds have made it to harvest. Obviously there is an issue with good genetics on the free ones. Strawberry Blue, Grapefruit Krush and Emerald Jack all either hermed or were too weak to keep, they were all free seeds. The only free seeds I can remember making it to harvest of late were Cotton Candy and N L X Big Bud.
It makes sense to me being I have actually grown a fair amount of freebies. I guess rarely was a bad word to use, but 50% sucks in a perfect environment.