I won't do those until a master piercer walks me through it. Those are extremely serious piercings that need to be taught. Everything can be pierced. At Gotham we have policies, though. We don't do surface piercings, like the forehead, the nape of the neck, across the back of the wrist, things like that, where there's no edge.
People come back and complain.
It's better not to risk the possibility of a lawsuit. There are also people piercing deeper than we feel is safe. Quite often, they're not so good. If the piercer has a good reputation, they're probably doing good work. The other way is to ask questions.