I hate to drag up a thread that had already died - but the most recent Guitar Player mag has an article about the Rolling Stones that may be relevent to this thread.
The Stones have been referenced as an example of the drums playing "behind the beat" or having a loose pocket.
Bill Wyman (bass player) pointed out (in the Guitar Player article) that unlike most bands (in which the band follows the drummer) - the Stones follow Keef's Guitar - including Charlie (the drummer). Anyone who has followed the Stones knows Keef has a tendancy to play loose and even turn the beat around on occasion - and pretty much expects the rest of the band to adapt.
So - Charlie may be a hair behind the guitar as he watches Keef for visual cues or simply because Charlie if trying follow Keef's less than precise playing. This by default places Charlie in a position of laying back - a little - which contributes to the Stones oft times loose pocket.
For what it's worth