There's a few here that are notorious for having ear buds in at all times. And if their name is known here then I'm sure it's at least talked about elsewhere including mainline. I get the whole "I want to talk to my wife and kids whenever I can" but while walking with a crew to an airplane it just looks not only unprofessional but if I was a nervous flyer I'd assume that captain didn't take the job seriously and would get anxious. It's a hot topic though, there's a whole thread on it on the majors forum and some people defend it. Times are changing I guess.