Given the harmful effects of sonic weapons, deployment of them in public should not be lawful absent specific legal authority to sanction specific individuals for crimes, as government is not authorized to randomly harm it's citizens. While they may not want kids in parks because sometimes some kids vandalize parks, that does not create authority to harm all kids that may be subject to such a weapon deployed on lands they have ownership interest in.

This is a crime against humanity, and I hope affected parties institute legal action forthwith to end the assault on their persons executed under color of law.

Thanks!