WHO WOULD HAVE THOUGHT OF THIS

In all of the excitement of a child's first time being away all day from home. And the joy of watching this child ride this big apparatus on a weekly journey to start his life in education. We were hit with a big blow, to our mind. Something that was incomprehensible.
How little person was choked on his way to school, by a fourth grader. My question was: 1. Why is he seated on the back of the bus? 2. Why is he on that set with a fourth grader? 3. Where was the bus monitors eyes at? 4. Why wasn't my grandma informed , when I arrived at school?

NOW WHERE IS THE LINE DRAWN IN LIABILITY