Saintprudence TimGER One thing is certain: you might not get what you want, but you'll get what you deserve.
That is why I prefer to caution against a keyholder that is already an authority figure for reasons other than consensual power exchange to the wearer. You may get more than you bargained for and have no way of terminationg that part of your relationship - which seems great for holding you accountable, but can cause serious problems when the situation develops into something truly unforeseen.
Another reason is that it might unintentionally come across as a kink thing, and something like that should alienate any reasonable parent.