And for those that are too lazy to go check that link (nice research gary,,) it will dehydrate the vocal folds and that will be bad for them as in straining them. So doing that, even the day before is a bad idea.
It would lead to the singer to have nodule on their vocal chords earlier (one of many factor). They'd then need surgery,, and basically finish one's singing career.
That why singers like Madonna (and she had wild days,,,), Celine dion (I know they're not good example in this case, as Instinct are a rock band, but they're the only ones that I know for fact) won't use alcohol at all during tours and recording period.
Granted, you'll hear about band and artist that seems to be famous on drugs and all those things,, but they're more into making themselves talked in the news and selling albums than to preserve their instrument and having a long career.
And I like to think that Instinct are more than a "I'm in for getting all the money while I can" band.
BTW I gotta say,, I'm surprised that no one is screaming cliffhanger!!