Casimir, surely you have played siege before. Every map with ladders has protection for defenders on either side of the ladder, where they are shielded from ranged. By the time you can even see the mauler, you are within their overhead range. The only "counter" is to pour in like lemmings, hoping a few people make it past the gauntlet. Idiot attacking archers that stop on the ladders always prevent this though.