It may very well be that they used the seax in all kinds of positions and they often DID cut themselves on the edge but refused to change it out of laziness or some sort of affection for the style or, hell, maybe it would have meant everybody had to get a new sheath as well.
Considering their sheath designs, I'd bet that combat often took place with a reverse grip. (a good combat grip)
That would turn the arm and knife into a hooking, cutting type weapon not unlike the kama.
That's all just speculation, of course...