One of the other callers ran into trouble calling two dances that were much too hard for the group. The first one needed two walkthroughs, and he couldn't drop out on the calling. After that, I would have chosen a dead easy dance and called it, but they pushed on and walked us through three walkthroughs of an even harder dance, which was shaky from the beginning and really fell apart once they started leaving out a call. They just kept calling, and the dance fell apart, until ending the music early. I saw this caller do this before, actually, at a dance I was playing for, where it was too hard and fell apart, and all they could do was keep calling the same too-hard dance. Which made me formulate two things that I've kind of thought for a while: (1) you need a backup dance and (2) if you just did two walkthroughs and they don't have it, don't do a third, call the backup dance. My normal backup dance is midwest folklore. It feels like a contra dance, but it's so simple you can call it no walkthrough if people know circle, dosido, and swing. And simple enough I have it memorised. It's also a becket dance ending with a partner, which means if a dance you're calling falls apart you can get people to swing their partners for the B2, and then start in with the dance. Ideally we would all be good enough callers to never choose something too hard or make a mistake calling, but having something to fall back on if things go wrong lessens the risk.