It would be a lot easier if everything was just catch & release. Only other option I could see would be tags for all species and for it to be mandatory to carry a scale & tape in the same way as it is to carry a permit.
ADAA do take positive steps to make sure that their members are obeying the rules in my experience but, there are a lot of members and a lot of water and like any organisation or association, there will be a few numb skulls. The majority should not be tarred with that brush and, there are still plenty of butchers fishing on non ADAA waters pretty much unchecked,
As far as big fish go, there is still this misguided nonsense about "cannibal trout" and I still hear it from some who really should know better.
For browns, we had 904 recorded catches, of which 862 (95%) were returned.
I'd be absolutely astonished if that was the real total, Iain, and I'd be very surprised if the locations and weights were accurate in the case of good fish. Not really sure that the current method or channels for recording trout catches really encourage accurate submission of data. It's a little different for migratory fish.
Cheers
Ben