Beags
Don't think the G2G between ATC and CRC had much to do with 9/11 - albeit that the ATC guys might have left it a little late to do anything about the 4 jets that weren't doing what they should have been. Once the QRA were airborne I think they pretty much got their way - the fact that there were 4 (count them) 4 Q jets for the entire eastern seaboard of CONUS might have had more to do with it.
On the original ADPF point - have you SEEN a radar display showing the London TMA recently? I only do surveillance and it scares the c*&p out of me. I've seen controllers go the scariest shade of white even taking jets to the edge before handing them over to LATCC. You CANNOT just turn the traffic off - it takes time, and this is the most efficient way of doing it at the moment.