Far from being the negative that some feel determined to find in any Air Tanker story, the ability to offset the cost with airline sub-charters was, from the very start, a major selling point of the contract. If it were needed in a national emergency it's never more than 12 hrs away, another 25 minutes to put "RAF" stickers over the logos, yes a full repaint takes longer, so what?
Cuba would in any case be a last choice for any unsched div. as a bureaucratic nightmare -in any aircraft. But if it was a life-or-death emergency, well, land then argue the toss later.