I guess people can only talk to their own experiences, and I realise you (Mbp) are more experienced than me with teens today. Do you think it's more than 3-4 kids in a school? -- the stat cited by the detailed summary of this latest study.
Teens at school 'in my day' were often dreadful, chronically disruptive and I always knew I would never want to be a teacher because of it. Though we didn't have knife carriers, admittedly. I was in the high academic stream, though,I think it was a lot rougher in the classes for the less able kids.
How do the parents prevent the school punishing the kids nowadays?
Thing is, people swear more now than they did 20-30 years ago. Fing and blinding like mad, it's not a big deal to many people to say F'off, the parents may literally think that way, not perceive it as you do (and as I would, too, mind). That's a cultural thing.
Knives is different, but are the excuses you cited due to parnts spoiling their kids in every way, as the report was talking about? Or just trying to find some way to get the kid back to school.