The obvious problem here is that not only did he put himself and others at risk, he put his own ambition (a pretty dumb one if you ask me), ahead of respect for space that is meant to be traffic-free. It's a bit like some annoying idiots who sometimes ride their scooters/motorbikes along the Bristol Railway Path (I was once almost hit by some twat on a trials motorbike who did this. Luckily, he was nicked).
What if he'd crashed and needed mountain rescue?. There is no difference here between this guy and those who insist on driving on pavements, barging into the ASL and whom have the attitude of 'I can drive anywhere I damn well please'. Cheeky sod couldn't be arsed to drive down the mountain, now leaving others to deal with it. He should be charged with littering amongst other things.
I am of the belief that some spaces in our green and pleasant land should be car/motorbike free for us all to enjoy without a ton of polluting metal and plastic spoiling it . This twit has now encouarged others to do the same. I understand that the National Trust has a problem with illegal motorbikes ridden carelessly on it's land, spoiling the surfaces which get churned up. The last thing we need in wild areas like this are dumb 4x4 twits. Since the majority of UK residents live in cities, why the hell do they need a vehicle capable of going up mountains?. It's about ego, nothing else.
I hope this guy gets a driving ban. Then, without his wheels to which he is no doubt addicted, maybe he can reflect on being silly

.