You can miss chord changes and just tell people you have a different version.
Sometimes, when I do workshops, I start by having the guitar players just play the chord that names the key. If you're a guitar player, try it: get a fiddler to play "Arkansas Traveller" and just play a "D" chord, all the way through. It's not great, and musicians will wince, but most dancers can't tell "Beethoven's Fifth" from "Foggy Mountain Breakdown." They're there to dance to some fast, fiddle tunes, and the guitar's their beat.
If you really, really don't know a tune, you can get through it with Dave Firestine's Universal Chord. Afterwards, people will run up to the stage and tell the fiddler, "You guys are really hot tonight!"
Because if they're listening, they're listening to the fiddle -- the melody. If the band sounds hot, or even just different, it must be the fiddler, who, by inference, must be leading the band.
This is why it's even okay for fiddlers to spring a new tune on the band at a dance. If the fiddler can get through it with confidence, and the guitar player (bass player, piano player ... whoever all has the bottom), keeps time, it will work fine for the dance.
... unless it's a waltz.
The single most common, intermediate fiddler mistake at dances is to say, "I have this great new waltz. Let's do it." Uh-uh. No. Not even with sheet music.
These are fiddlers who know how beautiful the waltz sounds in their heads, and what great vibrato and ornamentation they've put in, in the arrangement they've been practicing all week in their bedrooms. They know that when they do this waltz, the room will swell with romance, and after the last note, God will set off bottle rockets.
The grim truth is that waltzes are the only tunes that the guitar chords make or breaks. They all have thirteen different chords, and they're so slow that every one matters. A fluffed chord in a waltz is a gigantic, audio zit.
If you're the fiddler, you can do a new waltz before the break if the guitar player's heard it before and you have the chords written out. If he's never heard it, you can still do it as the last waltz if you bring charts and rehearse it at the break. Really. Listen to me on this one. I am not kidding.
If you're a guitar player, and it's waltz time, and your fiddler turns to you and says, "Let's do this new waltz. Here, I'll play it quickly for you, so you can see how it goes," shake your head, point at your lips and say, "No."
Your band's dances waltzes will sink or float on the guitar or the piano -- the figured bass. And after the ones that soar, dancers will run up to the stage and say, "Oh, that was so beautiful." They'll say it to the fiddler.
