I'm not a big fan of authenticators but they do serve a purpose. Think about how many items they get each month to authenticate. They get the new guys and the vintage stuff to examine. Often times, they err on the side of caution. Case in point the Jordan example above. A living player example of someone like Jordan, Jeter, A-Rod, or Pujols acquired IP is almost never passed these days. Why? Because those authenticators don't want to take that risk. I understand James Spence, at JSA, checks out a vintage item twice, sometimes three times, before he puts his stamp of approval on an item. Authenticators also do a lot more research than you or I would do. For example, I don't recall which company, whether it was PSA/DNA or JSA, who uncovered about a year ago another example of a Ted Williams clubhouse ghost sig on team balls from a certain period in the '50's. For years these were considered authentic and now are considered clubhouse fakes. Williams wasn't by any means the first to use a Clubhouse attendant to fake his sig and won't be the last. Authenticators bring those to light.
Are sigs still certified as authentic that still aren't the real deal? Of course. You're paying for an opinion. Who knows how many sigs that authenticator looked at that day before authenticating that one. When mistakes are made I don't think it's because they are lazy. It's probably because they are human. Humans make mistakes.