About 25 years ago a band I played in were on a radio show. I played guitar for the first of two songs and banjo for the second. The first tune was in Bb and the second, I Saw The Light, was in G. The guy who played banjo for the first song took off the capo and we traded instruments. I played the intro to the second song and it sounded terrible. By the time my solo came around I had discovered that the fifth string was still capoed at Bb and fixed the problem. I had friends who taped the show for me and I still have a cassette somewhere of that terrible intro.
I'm comfortable enough in front of an audience nowadays that I'd make a joke and start over. I'm sure Don's thinking, "I should have..."