I suppose you could say that delineating a space by constructing a ditch or bank or both, or erecting stones in a circle around a space, is a way of laying claim to that space for some use or other. But suppose it wasn't like that for our megalithic circle builders? Suppose it was the space without that was being ordered not the space within?
Perhaps the space within the circle was seen more as the primeval sanctuary, a vestige of a place before the world was cut and ploughed and made to come to order? Perhaps nothing much happened within a circle at all - perhaps it all went on on the outside.