Not taking a back seat, just interested in reading everyone's replies/opinions.

I agree that it's not exactly the most important thing in the world; or even in the world of folk, haha! But I think it does spoil the line of the instrument, and thus detracts just a little from the performance - especially if accidentally left on.

Imagine Leonidas Kavakos performing Sibelius on a Strad at the Royal Festival Hall, with an electronic tuner attached to the scroll of his violin! Okay, we might only be performing to a few fellow folkies in a draughty hall on a wet evening in November, but performing we still are; and a part of that performance is how the instrument looks.

It only takes a second to take the thing off and pop it into a pocket or bag! It will still be there ready for the tune-up before your next song!

Andy