there has to be a more efficient way to deal with these bloody things!
You need to understand that there is a very good reason why no one will sign such a declaration without full verification - how do we know that you are not getting the passport without the consent of your wife? Next thing you've taken the kids and it will come back on the person who signed off on the application.
Over the years I've signed many passport applications and I would never ever sign a form involving a child unless I was absolutely certain it was all in order, not even for a friend.