Well said OldGT. There are ignorant & selfish d1cks in all types of activities. And if someone is going to go onto private land in the middle of the night to illegally detect, I don't think it would make a shred of difference to them whether or not the authorities ban the hobby or close off state forest.
Here's one suggestion (and just wait a second while I climb into my bomb-proof bunker, and put on my bullet-proof vest)- Those of us who detect for gold (as opposed to those who like to shoot coins on the beach and in parks etc.,) pay a handsome price for our equipment, coils and so on. What if, in auriferous areas, or specific areas say like the golden triangle, there was a fee per year permit for prospecting anywhere other than your own private land, or other private land that you had written proof that you were allowed to detect on? I've only ever heard of one person having their credentials checked by the authorities while out detecting, and it was the guy who I bought my GPX5000 off of. He was detecting the Rheola hill area with a few other guys when a parks bloke pulled up, checked what they were doing, and asked to see everybody's prospecting permit.
If the money could actually be used to help fund such checks (let's face it, if you've got nothing to hide why should it bother you?), and it was backed up by big fines for prospecting on private land without permission, detecting without a licence, sh1tting all over the river bank and letting your crappy toilet paper disperse in the wind etc., and recorded visual proof of digging a huge crater and then walking off and leaving it unfilled, it may make a difference. We'd have to be sure though that any money raised from yearly fees and huge fines went back into the infrastructure of the system and not general revenue.