Since the wonderful new Edit Suggestions tool has been released, we have seen many (too many) suggestions from well-meaning users in the US to change speed limits to values like 16 or 31 mph. Obviously these users were set by default to use metric units without realizing it.

If a user tries to edit using the WME for the first time in a country that uses Imperial speed limits (which I believe is only the US, UK, Anguilla, Antigua, Barbados, and the Cayman Islands), their units should automatically be set to Imperial by default.