Disclaimer: not involved in this in any way. I was in the park with my elderly mum today and we sat down while she got her energy back to walk home. There were a couple of women there with 6 children between them running around, climbing trees etc. No problem with any of that. However one of the children climbed a 12 foot wall, stood on top, pulled off a loose brick and threw it onto the path just a few feet from us. One of the women saw all this, ordered a second child not to climb up, but said nothing to the first. Even that isn't my aibu, but just given to add context. She started to walk back to her friend with three of the children. One either side and a third on a skateboard next to her. A woman overtook them (socially distanced etc) and as soon as she was past, the child on the skateboard sat down facing a way from her and propelled themself backwards into the back of her legs. She staggered back, just managed not to actually fall but was limping. Not only did the child say absolutely nothing but neither adult with them made any attempt to apologise. (as confirmed with woman who was hit - we were the only ones to check she was OK - though bruised and shaken). Aibu to be horrified?? (nb my mum is 85,had a stroke last autumn and is pretty frail which may be colouring my reaction. The park is across from her house so the safest place for her to walk to and from, but I don't think she would have been able to stay on her feet if this child had cannoned into her)