OP, I bet you wished you'd never posted now!
There are some very odd points of view here and an obsession with thinking that if you had been sitting next to your 6 year old this accident wouldn't have happened. And how could you have missed the drinks trolley coming through as no-one in the history of flying has ever ever ever missed a drinks trolley 
So say that were the case, and you were sitting next to child, and for arguments sake you said that yes she could have a hot chocolate...
Then the 6 year old [not 2 or 3 year old] might still have spilt the 'too hot' hot chocolate and hurt herself.
How would OP sitting next to her child and noticing the drinks trolley have solved this issue? I guess she could have said no to the girl having a hot chocolate but why? Children have hot chocolate made by parents and cafes all the time. Or she could have held the cup to the girl's lips for her but she is 6 years old, not 2, so again why?
So maybe, just maybe then the OP should let the airline know of this incident and that cabin crew should really offer hot chocolate to children that has been cooled down with milk and also perhaps has a lid on it.
Why is this so hard for some of you to understand?
The poster who said that the OP would not be able to locate the life jackets in the event of a plane crash due to being sat behind child and having nose stuck in a book really takes the biscuit
and 