I don't think I could ever interfere in a family matter in public. It's difficult to tell who would welcome a round of support and who would punch me in the eye! But the little boy who was trailing behind his mother in the grocery store and having a whining hissy fit, got the "you better hush it, bud" look from me and his mother spun around FAST because it stopped. I just grabbed the canned pears off the shelf and put them in the cart! ("Who me?????")