The check box would leave a comment attached to the users name, so accounts like sunsetjesus which has no comments, no post and does nothing but down vote can be lowered a significant amount. If with the changes above a minimum reputation level was required to down vote, then that kind of down vote only account would disappear in a flash.
!ENGAGE 15
True. I like the minimum reputation to downvote part, too. Not so low that a new comer would be excluded, but a brief history of malfeasance would be enough to knock the out of commission.