A good question! I too use the hands down as I find they definately protect my own Shellac'd Nails. I have got into the habit of, after I've 'hand's down', I quickly swipe each finger with my right hand fingers to remove any odd fibres off their nails seems to work. (Client doesn't know what the heck I'm doing, but it's so quick and it works!).
Yes but they still get caught in dry bits of skin and things aswell so they are sometimes still there.
And I don't think your meant to touch the nails at all after scrub fresh as then you are or could be transferring oils and things again.