Yes, that would seem like a good idea. Or, simply make sure that the router notifies of not only changes to the parental controls, but also changes to the notification settings.
In other words, the notification settings could be changed, but, upon submission of the changes, the router would send a notification email to the previously saved email address.
I would think, if this could be done, then maybe multiple passwords would not be necessary.
I suggest this possibility mainly because I am the admin of our home network. My wife doesn’t have any expertise and really doesn’t want to know anything about it. However, as you might have guessed, I am also the one wanting to keep myself from the inappropriate content. So, I need to be able to make adjustments to the parental controls from time to time to improve how it’s working for various individuals in the house. But, at the same time, once I’ve got restrictions set, I need to make sure my wife is at least notified whenever I make a change so that she can drill me about it.