Just as a follow-up: I have seen (live) Pete Seeger, Theodore Bikel, and others blow a song and either cover it very quickly so that most people didn't notice, or, if really obvious, just shrug it off, usually with a chuckle, and keep right on going. Audiences are very forgiving and quickly forget it (as long as the performer doesn't make a big deal out of it!).

On one occasion, Segovia blew a piece really badly and covered it so well that the audience wasn't even aware. Bob Flanary (my classic guitar teacher at the time) and I did notice it, undoubtedly because we both played the piece ourselves.

Dealing well with boo-boos when and if they happen is part of a musical performer's art.

Don Firth