The singer does indeed decide.

I remember that particular evening, Rob - a most uncharacteristic comment in that session. I was also irked by the remark because I recall urging you (at the previous High Brooms night) to capo up to get the best from your voice!

Nowt wrong with Eb either... It's also always interesting to hear the snick of capos being fitted to guitars when someone starts a tune or song in an "odd" key. I never use a capo at sessions for accompaniment - only for singing using a specific guitar voicing. We get the occasional piper playing in F and - at the last session - one great piper from Belgium playing in Bb. Those keys are no problem for me after years of playing jazz. But of course even Homer nods and I can cock up an accompaniment as well as the next player! Normally, if I can't hack it, I shut up rather than capo up.