by vyran
You can't attack over bodies of water except where explicity shown on the board. In Risk 2210, the designation of being able to travel over water is even more blatant than in others, such as the road-like path between South America and Africa, and colored lines at the edges of the board where you can move to the opposite site.Since ESA and Canada have no such designation, no, battles can't occur between the two regions. Same with Nunavut and Quebec. I would say what you quoted from the rule book was either a misprint or a misunderstanding from the writer.
But, as rukiosu said, if you really want to allow it, you can. I would recommend trying the game as it is first though, and if you do decide that it would be beneficial to allow that change, make sure all the players are aware of (and accept) your house rule when you play later.