Hi Pilot Pete,
I mean theoretically you could fill up your tanks, let’s say for A332, 109 tons and fly for 13 hours where ever you want, and still have about 37 tons left in your tanks, but I don’t see any practical relevance in what you are saying. Fuel wise, the main requirement in terms “of in flight fuel management” is, to have at least final reserve on board upon landing anywhere on your route, so that the only restriction fuel wise. I think the whole purpose of commercial flight planning is to carry as much as possible payload and as much as only necessary fuel, in order to do that safely the authorities have put some rules and restriction.
If we are talking about some private flights or VIP flight, then the only rule there is just fill it up to the random regardless of where you go.
Again theoretically if you have enough fuel to reach any aerodrome you want, you don’t need any alternates or whatsoever, unless you are operating over remote area.
The whole idea about commercial aviation is based on reducing costs, but the task of the authorities is to enforce the airlines to operate safely.
Sorry it’s gone a bit hypothetical, but I think that’s the main matter.
Cheers.