Re: "traditional musicians don't use concert pitch." There isn't any such thing as concert pitch. James Galway, the famous classical flautist, has toured the world, and he says that pitch has been highest in Germany and lowest in the United States. The A that symphony orchestras tune to is the A on the oboe, not a common instrument for sessions.

However, I think tuners are a great idea. When I got a tuner and tuned by guitar to it, the guitar was suddenly twice as loud and mellow as before. For once, it was tuned to its proper resonant frequencies. Also, if you don't use tuners, people can spend much of their time tuning instead of playing.

How many beers had the unhappy guy had? That's got to be part of the equation. I have no sympathy for him.