i was actually wondering about the same the other day, when i spotted two old claims near the border, but they were both like 12 - 15 tiles away from it
Scott Burton: You shall pay toll for passing the bridge, or else the Troll Below the bridge shall consume you!
Very interesting thought. One problem is that I believe every so often they do increase the map size, meaning perhaps one day your most impenetrable wall becomes your weakest.