It was mentioned here that the Fountains of Wayne nailed the harmonies on
Craig Ferguson show last week.
I watched that too, but I got the distinct impression (based on the audio
quality of the backing vocals, that they were being backed by a track) The
song they did is very production oriented and I've heard a lot of live acts
sound thin on the Late Late Show's tiny stage area. I also remember that
they never nailed Stacey's Mom back when they were doing the TV rounds, my
guess is that they wanted to avoid that happening this time out.  I am sure
they were really "playing" live and even singing, but like for instance on
SNL, I think they were boosting the backing vocs and maybe some keyboards,
with a track.
For the record, i am not dissing them if they did this. It's a TV show not a
live band contest, whatever makes it sound better on the TV is fine with me.
And I know they can play live in a live setting, so no offence meant.  Oh
and as long as I'm covering all bases, my apologies to them if they weren't
using a track, perhaps they've been rehearsing the backing vocals to get
them sounding as pristine as they did on Craig's show.

My two cents.

Paul