Statistically 3 deaths amongst 50,000+ castmembers (or whatever the current employee count is after cut backs) is really quite low. In our warehouse, with 300 employees, we lost 3 people last year due to various causes.
From accidents? Or just people dying from natural causes? I would assume that Cast Members pass away from non-work related accidents, illnesses, natural causes, etc., all the time - it just doesn't make the news. For your workplace, 3 people out of 300, that's 1%. If all of those deaths were due to workplace accidents, I would think OSHA would be shutting things down, and local news would be all over it. At my workplace of about 1800, which is primarily composed of factory and warehouse positions, I'm not aware of any work-related deaths in the last several years. A 1% annual death rate from workplace accidents is pretty high! I'm hoping you meant 3 deaths from non-workplace related incidents.
I would say that three workplace related deaths out of 50,000 cast members in a single year actually is actually pretty high, given that there are very few jobs at WDW that are unusually dangerous or hazardous. Sure, there are stunt performers and drivers, fireworks and pyrotechnics, but that's a tiny percentage of WDW's workforce. Before the monorail accident in July, I can only find records of two cast member deaths since 2000 - the CM who was struck by a parade float backstage in 2004, and the CM who fell at Primeval Whirl in 2007.
Of course, of the three recent deaths, only the Monorail incident involves any culpabiltiy on the part of Disney. The other two were just freak accidents, sad and tragic. It's truly a bad time for Disney, and my heart goes out to all of the affected family members, friends, and fellow cast members. I can't imagine what it must be like - it must seem like the place is cursed right now.