I (and I suspect many others) am grossed out by that sort of body jewelry. If this flight attendant wants to wear it on her own time, when she is off work, that is totally fine. I would never presume to tell someone else how to dress or what kind of jewelry to wear on their own time. But this FA is working in a service position representing a major travel corporation. It behooves her to act and dress professionally (in a manner that will not gross out her customers), and if CO does not have a dress code prohibiting that kind of body jewelry, they should.