I was a teacher for a few years and in the years I taught I saw behaviour getting MUCH worse and parents getting less and less inclined to support teachers.
I saw a facebook post today saying that it's unreasonable to blame parents for children's behaviour in school and it then went on to talk about how hard it is for ND kids to stay regulated at school and it's the fault of "the system" that they can't cope.
There's a family I know with 2 boys who are both constantly in trouble in school. The classroom frequently has to be evacuated because of the younger one's violent outbursts. He's about 8.
I saw him today in the library, running around, ignoring the librarian, and swearing profusely the whole time. They're both always out unsupervised, roaming the streets, and when I see him with his Mum, she speaks to him with the same language he uses for everyone else. Social services had to get involved because she kept smacking them, so now she swears and shouts at them and they hit her, and she asks what she's supposed to do now she's not allowed to hit them back.
I don't know if they are ND, but the problem is that they're barely being parented and when they are, they example being set is dreadful.