It's more widespread to be wary of people than goods. Goods could be handed off at trading posts and in fact were rarely carried end-to-end in one go. There mi

It's more widespread to be wary of people than goods. Goods could be handed off at trading posts and in fact were rarely carried end-to-end in one go. There might have been a flow of goods, but it's doubtful there was free of movement of people, both as a practical matter of surviving a long journey, and having to explain oneself to authorities. The few documented adventurers and ambassadors travelled with an entourage, and news of their arrival often preceded them -- which was often necessary to avoid hostilities.