Confusing rules
I think AEF is suffering the same fate as ATC Gliding; in that the rules have escalated to the point that actual flying gets more difficult to achieve just because they have increased the 'operational' limits to operate.
We all know how the Gliding got 'paused' and how difficult it is to 'un pause it' due regulations, plus lack of suitably trained and current staff.
The AEF operation has been made even more 'complicated' by insisting on a cockpit warning system, plus has to operate under an Air Traffic service.
Neither of these is a substitute for the real basic airmanship operation of LOOKING OUT. Once you try to substitute a basic VFR rule with anything requiring 'equipment', and an Air Traffic service you merely add yet another level of conformity that has its own level of serviceability and operational limitations.
The AEF issue no doubt was influenced by the fatal accident some time back.
However this rather overlooked the fact that there was a human failing element that predominated over a system failure and rather like the Shoreham Airshow situation it is difficult to impose yet more rules that do not really rectify something that should be covered in NORMAL airmanship.
If you fly VFR YOU LOOK OUT and if you fail to do this then you are negligent. Relying on radio and 'warnings' is no substitute ever.