There's no way that doesn't roll back up when you hit the first pothole.
I dunno; by hand you need to be very deliberate about rolling it up. I don't doubt that it
can be accidentally rolled up, but someone who has used one for a while will be able to say if this happens or not when you are riding, and if so when/how often exactly.
Note that the downwards impulse won't provoke a roll; only an abrupt upwards impulse will do that, and such impulses are usually damped by the Mk1 backside in the saddle.
cheers