That seems very awkward versus a laptop, though; in particular you'd have stay very still. I'd expect it to be particularly problematic on a bus or train, where there was movement.
The hinge is sturdy so in comparison with a laptop you don't have one big contact area with your legs but the bottom of the kickstand and the botom of the machine itself which don't move with respect to each other. The bottom of the keyboard kan move wrt the rest but only in one plane. I don't see how movement of whatever you're sitting on changes much in how the thing sits on your lap. I also don't encounter that when I'm on a bus or so.