Unfortunately,going by the experiences of my children/grandchildre/and now gt grandchildre,it is just this " jostling and name calling" that lead to more serious bullying.
Children are not like adults(obviously) and they do not think of the conswquences of their anti social actions.
They will try out the jostling and name calling,and when they find a child who doesn't wan to get involved,OR actually shrinks away from it,then the "hard" bullying will start.
Sad to say some schools have an ehtos of such behaviour in children,and teachers look on it (like the lady on the radio) as being part of growing up,IT ISN'T!
Because of this ethos bullying is swept under tha carpet,and ignorde,often with fatal consequences.
Too many children (even today in the 21st century) are severely bullied,but because teachers are unaware,or actively ignore it,the children are terrified to tell anyone.
So remeber,this supposed "normaL" jostling etc is not normal,and allows bullies to prey on children to weak or terrified to report it,or hit back.
We had such actions when I was at school(I am 86) but I ha hoped to see the ned of such actions,obviously I won't.