Never mind the parent being able to shock them. The frequency should be universal so the rest of us can get 'em, too.
Make them wear tags.
"IS THIS CHILD MISBEHAVING? SHOCK CODE 2918."
School just started up in my town. Parents were hovering around their sprogs at a bus stop along the path where I ride (bicycle) to work. I thought, "Oooooh yeah, I forgot about this weird behavior."
And a moovan showed up and dropped off a kid! WTF! It can't walk a few hundred yards? No wonder kids are so fat now.
A duh stared at me as I went by. Not sure why. Either he was sizing me up as a potential child molester, mad because I didn't dismount and walk my bicycle past the kids (I wasn't really anywhere near them), or he was ogling my bike because I just bought it yesterday and it's a piece of big manly testosterone generating mountain bike.
(Trek Liquid 25!) I can buy expensive bikes. I'm child free!