https://screenrant.com/why-cheers-opening-intro-change-live-studio-audience/

Cheers features a unique disclaimer at the start of every episode, which was added after the NBC sitcom received complaints from TV viewers.

"There is the mandatory "Norm" greeting whenever George Wendt's perpetually drunk Norm Peterson enters Cheers"

I don't recall ever seeing Norm drunk. Yeah, he was always drinking but would walk out of the bar in a very straight line to the door at the end of the day.