I would have attended one of the days over that weekend if my camera hadn't packed up the previous weekend and was being repaired.
I've been to Silverstone 7 times so far this season ( 200 mile round trip) and apart from the FIA GT/WTCC meeting it's been empty every time. Most events you can see more marshals than paying spectators around the Luffield area.
My local track, Castle Combe, on the other hand is packed out for small club events because they market the meetings and also run their own championships which attract a big following.