The cautionary tale for me would be Carwynnen Quoit, which fell down cos too many people climbed on it (I think).

To make a windshelter out of an upland cairns, you probably need a gang of strapping squaddies. It would take me a month to create a wind shelter out of one, by which time I would have died (of hypothermia, hunger, thirst or being carried off and eaten by an angry yeti).