I am not sure what you mean by "cut them a break". If any adult or child comes on to my property to play a prank on me, it is well within my rights to tell them i don't think it is funny. And I told them that, and told them I was going to post their picture on the list serve, and that they should wear masks. I did not say or do anything else to them. I can and will say I don't like it on this listserv, and ask that anyone who knows them to tell them I said it's not funny and they should wear a mask. I am not calling for their arrest or banishment, but I'd want to know what my kids were up to if I was their parent, and this is a way to get that message out.
As to legality I understand that you saw it someplace, I can't find a single law that says that and I don't think what you read was correct. If someone wants to correct me, please do - with reference to the law(s) that are relevant.
As for giving the school system permission to use your child's image, I saw that when I was looking for laws. Assuming your child goes to MCPS, it appears the form says the school assumes you agree unless you opt out - so that implies that it is allowed unless you request they do not. Part of MCPS policy for social media (also found online) states that employees of MCPS may not "post images of students in the classroom whose parents or guardians have not provided written consent" which seems to contradict the form a bit, but in either case these don't apply to photos of people in public.
Regards,