The better question is how quickly can a tech savvy kid (like so many are or have friends that are) beat or even remove any or all of the above restrictions?
Even if the parent can determine ex post facto that the kid messed around with the settings, who knows what terrible dangers the kid already exposed him or herself to. And then they may be able to cover their tracks (i.e. resetting what they disabled or reinstalling what they removed) altogether, and the less tech savvy parent may never even know.