Yeah ok.. but if the VFR guy has been at 9500 for 2 hours and is about to leave a level what is the difference between him/her and the IFR at 9000 doing the same ??
The IFR guy already gets passed known IFR and quite possibly observed VFR if in radar coverage..
If its so needed for IFR then would it not be needed more so for VFR with no traffic picture at all...?? (in VMC..ok..)
perhaps the safest idea is a large area around busy locations where people were required to all be on the one frequency and talk to each other to enhance safety without cluttering up centre frequency.. we could call it a RBZ.. cause we know a MBZ didn't work eh !!