Four degrees of separation

Just for the record, so we're all straight about this, and you'll tell me if I'm being unreasonable, right?

• If you are the designated person in charge of my child while I'm somewhere else, for five minutes or three hours, and he misbehaves, you are entirely entitled - nay, expected - to tell him off for it. With appropriate and not excessive force. I don't leave my children in the charge of anyone of whom I would expect less.
• If you are in the vicinity of my child when they do something they shouldn't, especially - but not solely - if your child is involved as the innocent party, and I am not nearby, you may by all means tell him off for it.
• If I'm right there but happen to be looking the other way when something happens, it's fine for you to admonish my child - but since I'm in your hearing, you might think about doing it in a way that's more about calling my attention to the event than about disciplining him directly. That would be tactful.
• If I'm talking to my child, looking him in the eye and taking him to task myself, right at this moment, for acting the maggot, please do not feel that you can improve matters by adding your voice of disapproval to the fray. Especially if you just met him for the first time today.

That's all. Kthxbye.