Geoff
You made some good points in your article, and made a quite reasonable argument.
I have witnessed picking in Witley Common, in Surrey, where large groups of people pick every mushroom in sight, then an 'expert' sorts them out, taking the edibles, and leaving the rest. I've seen them leave huge piles of rotting fungi. This is dplorable behaviour. Yes they do denude the area of macro-fungi. My concern is exactly the one that you express, that picking large quantities may well prevent the fungus from spreading to new habitats far away. Fungi produce so many spores because most will land on an unsuitable substrate.
I have not seen this industrial hoovering up of fungi in the New Forest, but I suspect it goes on.
The question that I would like answered is what difference will this make. Clearly they were not enforcing the 1.5 Kg per person limit, so why will they now enforce this new ban? Or will it make it easier to bring prosecutions, as there is no longer a burden on them to prove the person was exceeding the limit.