I have to confess that I am one of those people who struggle with the idea of putting my DS on Space Mountain, (some of you may have seen by previous thread on this issue but having said that he has done lots of other rides.)
I think Iain that you may have said what a lot of us are thinking.
it doesn't hurt to remind ourselves that even though Disney is a magical place the same issues around safety are still there ( just think about poor old Pluto at wdw )
I may be wrong but a 4 year old who measure 44 inches sounds quite tall to me, maybe as well has height restrictions they should put a age restriction too, so that if you have an exceptionally tall child it is covered by the age restrictiom and if you have a very short child it is covered by the height restriction.
When we were at WDW last year both times our DS begged us to take him on Mission Space, it was a plea that fell on deaf years, even our son who was a DCM wouldn't take him on it. The fact that the ride was made in such a way that you could hose it out easily and the fact they had recently installed vomit bags on the ride and the fact that several people had been taken to hospital after the ride not to mention the warnings gave a pretty clear picture . We all make mistakes but tragically some pay a much greater price than others. How I bet that little boys family would give anything to turn the clock back. Its so terribly, terribly, tragic and sad. My heartfelt sympathy goes to all the family and also to the CM's who were operating the ride at the time