Its cheap, just like throwing low blows in boxing. Sure you can get away with it but then you have no honor.
Take spies and ninja for an example. They fight enemies by using cheap tricks (poison the food, use a long ranged weapon so the person can't get to you. Its cheap, thus have no honor. Thats why the samurai hated when the ashigiru (peasants I think, could be wrong on that) got guns. They could shoot you in the back.
Its sad if you have to use a tactic like spamming to win.
Remember The ends does NOT ALWAYS justify the means, this is one of those situations