Man, if I had to tune anyone's instrument for them, I'd certainly do it as incognito as possible- to avoid *rank amateurish by association* status
Funny story...The drummer in my last band was in a relatively successful band years ago. They never got a record deal, but they came pretty close. Breaking Benjamin was just starting out and they opened on occasion for my drummer's old band.
Ben Burnley didn't actually know how to tune his own guitar. I guess Ben is (or was?) a relatively quiet guy, and he would sheepisly ask my drummer's guitarist if he'd mind tuning his guitar for him. Yep, the front guy for a major national level rock band was gigging and didn't even know how to tune his own guitar. I wonder if he ever learned. Of course, he's at the level that he'd have a guitar tech doing that for him every night.

