I have several sets of Contis including Gatorskins, GP4000's and 4-seasons. Many (if not all) have some sort of degradation to the sidewall near the bead. I occasionally see a thread dangling off the sidewall and I just cut them off. However, I rarely flat and have never had a sidewall failure.
I still buy Contis because they are cheap compared to the rest, and I've always had great luck with flat prevention. I do not over-inflate, either.