Is it just a little contrivance added to the script to make it seem more "real", like they actually had been eating?
That's the one I'd bet on.
I'd never really noticed the napkins before, but that explanation makes sense to me.
Oh, and congratulations! You've asked a really original question about L&C!
I've been around for eight years, and I've seen all the usual ones... It's a nice change to get a new question, and it keeps getting harder!
PJ