Although, I have to say, if the beacons:

a) were that quick to be lit
b) summoned the entire male population of Rohan on a three-day journey

...you'd have thought they'd have some agreed signal for 'Oops! Captain Barothar slipped while trying to light his pipe. We don't need you after all.' And if they had such a signal, why didn't old misery guts use it?

Yeah, saw it yesterday and really enjoyed it!