I agree it's bogus. Looking at her arm, you can see it wasn't "written" smoothly. It looks as though the person doing it had to stop and think about each stroke.
Also, if I was going to slash somebody's face,not that I would , I think I would do vertical lines as opposed to horizontal.
Yep, you would be looking to be doing it quick and getting the hell out of there. That means that you would be making the motions as naturally as possible (up and down and forget neatness).