There are information boards spaced out around the loch, and one is opposite the crannog on the S shore. I forget the name of the clan it talks about, but presumably it was the Robertsons of Struan. Apparently, if they were being chased by their enemies, they would head for the shore of Loch Rannoch, and run out to Eilean nam Faoileag on the submerged sand bank. Anyone trying to follow them, not knowing where the curved causeway was, would inevitably perish.