Thank goodness Taylor went home emptyhanded. Death @ them placing her pop album in the country category. As big of a fail as her thinking she heard "Red" when Alicia Keys called Random....
Why does Beyoncé insist on lip syncing when she can sing the songs perfectly by herself?
Vocal chord maintenance likely, though I believe Beyonce was live for the latter half of the song w/ Jay. There's a reason why when Celine sings live nowadays it's just like old times; her lipping back in her prime really helped maintain her vocal chords. Whereas G0D developed nodules on her vocal chords by 2000 and doesn't sound like she used to.
I don't think it's a big deal though. Most, if not all, voice-oriented entertainers have lipped @ some point. This should really only be a big deal to 10 year olds who just got hip to their idol.