Re: Probably mentioned already but
"You must be joking, modern parents won't even stop their evil progeny running all over the supermarket screaming."
Because if the parents stepped in, the scream would probably turn to "STRANGER! STRANGER!" and start raising alarm bells.
And the threat of spanking was countered with a threat of stomped feet---with hardened leather soles. I recall one mother ended up in the hospital with a broken foot from such an escalation.
Moral: It's not just the law parents fear but also the idea kids may be smart enough and bold enough to retaliate.