I have remembered more... I do not mean 'scuffles'; I mean incidents where the violence was bad enough that I wanted to involve the police (but didn't, after the first one - not two, as I said above - I remember he persuaded me not to in the end). And I am not including 'fights' - my DS has also been in several of those, though has also never started them. These were all occasions where the attacker was much bigger, and the violence seemed unjustified or totally disproportionate:
1st time: punched in eye and knocked unconscious when he was 13, by a boy 3 years older and very very much bigger, because he was rude and cheeky as they got off the school bus.
2nd time: punched in face and kicked on the ground when he was 14, by a boy 2 years older, also apparently for cheekiness.
3rd time: punched in eye and knocked unconscious when he was 14/15, at school, by a boy in the same year who the school told me 'had serious problems at home', for no apparent reason.
4th time: punched in face, kicked to the ground, kicked in face when he was 16, by a boy who was a friend at the time (but then wasn't, I'm glad to say) in an argument about money (and probably weed).
5th time: beaten up very badly this summer, and kicked repeatedly in the ribs and head, by a 20 year-old, because he had stolen a friend's phone when he was drunk. (He was very clear he 'deserved' this beating, but I don't live in a world where people ever 'deserve' being kicked in the head :( . He was also arrested and warned for the theft, which I say he did deserve.)
The first three incidents were definitely shaped by a culture of violence and bullying at the local school, which was not tackled by the head teacher at the time. My DS was hurt in a minor way most days (and many other boys were too I imagine, because it was not particularly targeted). It was quite brutalising. There is a new head who has stopped this kind of behaviour entirely, so DS2 has not experienced it at all, but for older local boys it seems quite ingrained. DS1 thinks that a much higher level of violence than I am used to is quite normal :( It horrifies me, and I don't feel I deal with it well.