No, what I mean is that we don't want places to have to be roped off and signposted to death in order to preserve them. I'm saying Carnac and Stonehenge are surviving, but at a price I think is very high - i.e the loss of being able to properly see the stones up close. One of the main reasons I've never been to Stonehenge is because of the comments made by many others about the lack of atmosphere and sense of place since the inner circle was closed off. And in fact your post highlights the fact that at Carnca the idiots who will climb on the stones will do so regardless of the amount of signs and barriers.
Re: upland cairns. I would hope that anyone who has read my previous comments on ther subject of walker damage to these would know that I would NEVER "create my own access". The comment about climbing "into" them was a recognition of the terrible damage that has been caused by walkers reconfiguring them for shelters, etc. These are not "chambers", they're wrecks. Take the cairn on Moel Siabod, you can't really do anything but go "into" it, as the centre has been completely removed by walkers.
Generally the purpose of climbing "onto" the cairns, rather than being "look at me" as you suggest is both to see how well-preserved or otherwise they are, usually to take some pictures, which itself acts as a record of the current state of preservation. See for example the pictures of the cairns on Western Beacon in Dartmoor, some of the ones that Lubin's previous post is referring to - restored then soon wrecked again by thoughtless walkers. You will note that the most vocal of us on this forum about the damage to upland cairns are generally the ones who actually go and visit them regularly (and report back on here), like myself, Gladman, Postman, Drew, etc. None of us are doing any wrecking by doing so, as far as I can tell, nor are we claiming "special pleading".
You can get up close and personal by arrangement to the roped off alignments at Carnac and around...the climbing is often done...more in the town itself where there is no signage...but usually viligant elderly residents with extremely sharp tongues and scant regard for the Geneva Convention when it comes to walloping trangressors about the ears protect their heritage...I have witnessed more than one chasing away aided by shouting and brandished rolling pin....I was actually in the process of berating a "climber" and his dopey friends in Carnac town for this...the party involved claimed to be Belgian and unable to understand my reproach...but scarpered when this tweed skirt & twin-set clad grande dame chased them off(putting my restrained approach very much to shame). I also should make it clear..it is the drunken "look at me" mobs who clamber and destroy for no other reason than self-gratification, I was aiming my reply to your post about....however I still think if they were to see any of us even innocently recording and creating records, even silently sitting and touching nothing taking in the atmosphere they would probably use the monkey see-monkey do excuse for their own behaviour.