I read something about that way back. Mick said something about that they sometimes ran into those guys and that they're still saying to EVERYONE.. really proud of it..
Yeah those percussionists got on a fantastic groove! Read somewhere that Jagger considered on taking them on the road during the 1969 tour. The wondered if they should play SFTD really long live (e.g. 25 minutes) or not. To bad they didn't otherwise they mighted have joined in!
I really like the Hyde Park rendition. It was the first time they played it live (not counting the Rock 'n' Roll Circus version) and I think they were trying to recreate the feel of the studio take. I think all the dancing guys and drummers really must've made it a carnival atmosphere. It was just perfect for the occasion.