In a dwelling unit, ground up or ground down is not going to make a bit of difference 99.9% of the time. (That is an official guesstimate)
1)Very few plugs that will be plugged in at a dwelling unit will have a ground prong, "to guard" the hot from thin falling metal objects.
2)Most dwelling units utilize non-metallic plates, so if a plate does come unscrewed and if it falls onto the prongs no problem.
Seems like we could worry about something really important.
Like "Should the lights go out when all 3 and 4 way switches are in the down position?"