So 411A, you would taxi back to your gate (if not already taken) and upload more fuel????
I think only a FOOL would contemplate going back to his gate at places like LHR, JFK and so on just because you burnt your contingency fuel.
Think about the time, costs of going back to the gate (holding to wait for another gate) refuel (wait for a refueller), taxi back out again (join the queue again) and then take-off???? The whole episode could cost you hours
You would have to be kidding!!!
I'm sure most would depart and then get the short cuts, altitudes and so on.
If then I'm short on fuel for my destination would I do a tech stop and refuel
(probably at some quiet place down the route). There's always a good chance you can make some fuel up.
I agree that there are some situations where I would replenish the tanks (short sectors with little contingency, along with bad destination wx),
411A needs to be somewhat a bit more practical.