i just can't imagine that it wouldn't be stressful for the snake to be in the shower getting pelted with water. besides that, her whole point is that she wants to save time by doing the two things at once--how is she going to bathe while not getting shampoo and whatnot on the snake, keep him comfortable and still save time? seems like doing both at once would actually end up taking more time.
personally, i prefer to wash up after i handle my snakes, not while i handle them. seems a little more sanitary that way anyhow, ya know?