Every hook manufacturer will let some substandard products slip out the door. When they are dealing with that many hooks its impossible to catch every sub standard hook. Ive had sub standard hooks with every manufacturer. Vision doesnt seem have more "bad" hooks than anyone else. They are a newer company and people are looking harder at thier products. Personally I will use nothing bt Vision hooks, I have yet to have one fail while using one. I cant say that about the other guys hooks.
I work in a production plant that produces a couple of million linial feet of material a day. Even though we make the best product on the market and our qality control is the best in the buisness we still let some bad stuff get out the door. That just happens when you are dealing with large volumes of product. It cant be helped.