as I read the rules, you don’t have to say where you plan to build your carriers. It gives ALOT of very specific rules on how you can MOVE your carriers, and what airmoves are legal, but NO rules on how to build your carriers.
the rules for airmovement says that you have to be able to land all your planes if you take 0 losses in every battle, and with possible carrier build.
it states that you have to follow through with carriermoves if they where decleared, also states that any carrier with movementpoint left in Non Combat have to move to help a ftr/tac land (even the ones not declared, example; the carrier you planned to land on was damaged).
it does however NOT state that you actually have to build your carrier in a seazone to safe a survived ftr.
so IMO, you dont have to mobilize a carrier anywhere, all you have to do is to be ABLE to mobilize it.
the main reason you might want to do this is if your carrier will be dead if you do it. example scenario;
, japan hits some US boats in sea of japan, kills all but the subs., US have like 20 subs in left, but no surface and japans fleet is next to indochina, then japan might want to let the ftr die, instead of moblizing in the sea of japan.
or, for some reason anzak have used some ftrs at maximum range to kill japanese boats next to sidney, but the seazone is not safe, Anzak had paid for 3 inf + 1 carrier, now that the Mobilisation phase comes, anzak have to chose which unit to get reimbursed for, so they chose the carrier.
and a number of other ways.