I don't know if you've seen it, Stilly, but The Register did a little checking with a VPN, and the Gulf of Mexico's only misnamed for people with (apparent) locations in the USA; the proper name appears for those in Mexico, and both names for those elsewhere. Google Maps do have precedents for that sort of thing, of which the first that comes to my mind is the English inability to name La Manche properly.

Apologies if this should have been in the Manbaby thread, but it's Google's way of coping with the Unreasonable.