No, not gonna happen.
a) "Are you sure?" screens are bad design. Look at Windows Vista UAC. All it does is teach the user/player to mindlessly click "yes".
b) What damage does calling early taxes do? It's not like it reduces the total amount of tax gold you're going to get. It just means you get what was in the Gold Collected pot earlier—which means there's not yet as much there.
The only possible damage I can see early tax doing is psychological, if people think you did it because you're desperate. If they think that, it's your job to convince them they're wrong.
(And if they think that, I would say there's already reason for them to suspect that the situation is desperate...)
