That isn't lip syncing. She isn't pretending to be singing the track, she's not moving her lips lol. She's just letting the track play while she dances & ****
Amy and the whole band didn't play live at some obscure music show in France or something back in the day. They didn't because they weren't aware they they would have to till they got there and I don't really know the rest of the story but yeah
I don't think anyone else in my sig ever has though but I'm not 100% sure
Gaga has never and will never . She will let the backtrack do some of the work sometimes, like in Sexxx Dreams chorus, HML, etc., but she doesn't lip sync.
Lady Gaga performed Paper Gangsta with excessive use of autotune, and has lipped a few parts of other songs too.
The auto tune was very clearly done on purpose for effect, just like it is on the album. Has to do with what the song is about. And she has had loud backing tracks at times but she hasn't ever lip-synced.