The hub is a Shimano Deore and I'm not quite sure why the dude I know has one that keeps failing. He occasionally rides trails but it's not like he's subjecting it to huge hits or anything.
The giant rear wheel has a lot of weight to it so maybe the force needed just to make the damn thing spin is somehow putting added stress on the pawls inside the freehub. According to the tech we spoke with at QBP, it's not a common problem but he had seen it happen more than once.