When your favorite band cancels their gig because the lead singer has "come down with the flu", that's industry code for "got too wasted, and is currently too busy getting alcohol and possibly drugs out of their system to perform".
I even worked one show that had to end after 20 minutes because one guy in the band was visibly under the influence, refused to play, talked to his hallucinations, then spent a few minutes talking to the audience about how his foot was evil and wanted to kill him, before the tour manager could drag him off stage. Then he tried to assault several backstage staff for not allowing him to cut off his foot. This was on a tour that promoted alcohol free rockshows btw, so we didn't provide alcohol to the artists backstage. God knows what he might've purchased from our local street dealers lol.
The next day in the papers, the headline says "[the band] cancels first week of reunion tour after flu outbreak" 🙃 Yes, of course
I always wondered why Paul Westerberg caught the flu so much. When I finally got to see him live a few years ago he definitely was coming down with the flu on stage.