I heard a story from a guy touring with the reggae superstar Peter Tosh. They played a big show in Italy. Suddenly the power went out. There they were standing in front of several thousand people. Peter then took out an acoustic guitar and told the audience to be as silent as possible. Then started to play songs acoustically from the front of the stage. He did this for a couple of songs then the power went back.
That is the professional way to do it. When the obstacle happens you just go around it. The artists that have been papered with usually can't really things like Peter Tosh did. They are freaked out if anything is not in order and the sound needs to be utterly perfect for them to do their thing.
In reality that is actually a sign that there not good enough. They try to hide behind a manager that demands different stuff that really is not necessary.
That is why I like to see an artist get into a showcase where it's only 10 people in the audience. There is a struggle with the sound and not the best stage. If they can master that, well then it's no worries that they can take on 50 000 people on Madison Square Graden with perfect sound and stage.
It might not be fun, but it's a good test if you have the skills to make it. And the understanding to know what to do.
One of these moments was when we played at SXSW with You Say France & I Whistle. We got to the gig place and the drumset that supposed to be there was just a mess. The floor tomb only had one leg. Instead of start nagging and drag out on the misery, the drummer instead went behind the bar got a box to put under the drum to solve the problem.