@ConjurerDragon Of course you are correct in your argument, and I don't mind since now that I am aware this rule would never be a problem in the future. For players who don't know this rule; is it really worth frustrating them? it will only emerge rarely for a player who tries to build a route, and then discovers this rule. No added gameplay - just potential annoyance. A better solution would be to forbid access to surrounded mountains. If a pioneer can't get there then the issue will never emerge.