>Crass? Yes I agree.

Good. :o)

>Useless prohibitive signs are crass as well as ineffective.

I agree.

>Could try iron cages for the boulders like at Kit Cody and the Whispering Knights, or perhaps some tasteful razor wire.

I don't agree with that suggestion by you.

>Ever heard of wear and tear - nothing is forever is it?

Yes. All of our exposed rock art will dissappear in time. :o(
Unlike you, I don't believe that sportspeople should be allowed to accelerate the process by clambering over our Scheduled Ancient Monuments.

>But I guess that's a crass observation too.

You said it - not me.

Baz