I'll skip the jokes about being bored to death by Small World and get right to the point. What's surprising to me is that people aren't dropping dead daily at WDW. My city's population is about what the average daily attendance (estimated) for one WDW park is so figure all 4 parks have maybe 120,000 people each day. Let's not quibble about actual figures, the point is that in WDW on any given day are enough people to fill a decent sized American city. Check the obits in your newspaper for a week or so, throw out the deaths by accident and violent crime, ignore the very old or those who die after a prolonged illness and you're left with some people who just, die, suddenly and unexpectedly.
The surprise to me is that we're not hearing ambulance sirens on a regular basis. I recall the last few deaths reported at WDW. One was a guy off his meds at Splash Mtn who stepped out of his log and was crushed, another was a teen from PA who died on or shortly after ToT who was found to have an diagnosed heart defect, same for a girl who died on Rock n' Rollercoaster, a German woman with known blood pressure issues who died after riding Mission Space.
Simply put, death happens and if you put a chair on a room in WDW and had an endless file of people just sit in it for 3 minutes then walk away, a number of people would die while sitting or shortly after.
Bill From PA