I'm just going to nit on your phrasing here. NANP and the associated +1 country code originated from the United States. Technically I am talking about "changing theirs." The fact that it's very reasonably shared with other North American countries in a manner that allows for plenary power on the part of each other member nation is the source of this issue. I'm suggesting the US revise NANP and put more conditions on sharing the +1 country code, although most preferably with a consensus of the other members.
Bad actors in different nations than consumers shouldn't be able to leverage sovereignty or agreements like NANP to be bad actors with impunity.