But an adult can't tell ahead of time if they have an UNKNOWN pre-existing condition so that in effect means rides are potentially not safe for anyone of any age.
In the instance of dehydration, it would not be Disney's fault (or the parent, for that matter, unless the parent was intentionally not allowing the child to drink, which I doubt was the case). When you are dehydrated, your body starts to shut down. Disney does have warnings up stating you should be in good health. Being dehydrated is not being in good health.
Using your logic, children shouldn't be allowed to play basketball because it can lead to death. When I was in junior high, a good friend had a heart attack and died on the basketball court. Nobody was aware of the fact that this perfectly healthy kid had a heart problem. I remember my mom telling me that my friend's mom was so devastated and she blamed herself for allowing her dd to be so involved in sports. Reality is, if my friend didn't die then, she could have died while on a ride in a theme park or maybe when a plane she was on took off. Her heart was defective and nobody knew. The problem she had was not something that would have been caught with a stethoscope. It is tragic but basketball is not to blame for her death.
Accidents happen every day in this world. It is tragic but it is reality. We take risks everytime we get in the car, on a plane or cross a street. If MS has a defect in the ride that can cause death in children and/or adults, then they are 200% responsible. I am NOT defending Disney. But the facts remain that tons of people (including many children) ride MS daily and they do not die. In the case of tragedy we are always looking for someone to blame. Sometimes there isn't anyone to blame. Sometimes it is nothing more then a terrible tragedy.
Lisa