system
Given the following post, respond as if you're commenting on Reddit:
human
[Matilda] How did the Trunchbull avoid being sued for the various injuries she inflicted upon the students?

It's established that for a lot of the things the Trunchbull does that the parents don't believe their children, but several of her actions cause injuries, so it's hard to believe that no one would pay any attention after a while.
gpt
Ronald Dahl based Trunchbull off his childhood. It seems outlandish now sure but way back when it wasn't that unheard for corporal punishment to be a thing. Historians have found evidence of spanking and hitting being used in schools in the 80's. Heck corporal punishment is still legal in half of the US. 

Also if you notice Trunchbull is actually fairly careful about her punishments. Her only punishment that leaves injuries is the Chokey and that only leaves small cuts.