US-based mapmaker Rand McNally, for example, changes national borders only when the US State Department recognises a change, although it will shade areas under dispute.
Given that it often drizzles in Wales, it is a good idea to pick up a laminated map of the relevant area from the Ordnance Survey, Britain's state mapmaker.
But allowing alternate maps raises other tough questions such as: Could a mapmaker use an existing map to safely navigate the Channel while making his own calculations for a new one?