In a recent game two battles were occuring simultaniously and one player had a number of cards in reserve, and a number of cards committed to bo th battles. Consiquently when they drew up to five cards at the end of their turn they had only just enough cards in their deck to do so. Since this was the Carthginian player it turned out the that just about every time they took a turn during the battles that the campaign event occured. This made me wonder what the protocol is if a player for some reason is unable to draw up to five cards. What happens then?
You draw up to as many cards as you can. There's no penalty for drawing less than your maximum hand size if you are unable to. Yes, this does mean you are going to have some very fast turns until at least one of those battles ends.
This kind of hyper thinning is almost certainly fatal for the Carthaginians in practice, because the Romans will get at least 2 actions before the next Campaign sequence. They should use these actions to expand (thus gaining VP) or to raid your locations (which you probably can't defend because your cards are all committed to battle or the Reserve).
In playtesting these kinds of games ended very fast (turn 7 or so) and always with a Carthaginian loss.
I should probably add a sentence to the end of the note on page 5:
"It is also possible that you might not be able to draw up to your maximum hand size because there aren't enough cards left in your Draw deck. In that case there is no penalty, just draw as many as you can."
Also keep in mind the note at the end of 4.1 that prevents you from entering into an infinite loop with the Campaign card.