For instance, the involuntary manslaughter charge is going to be hard to proof when the evidence that he was planning on going on the ride the same day is presented. They have to prove recklessness which includes proving the person knew their actions were likely to cause harm.
Also worth noting they are basically throwing the book at him with the number and severity of charges on the indictment.
Often the safety of something for a particular person depends on their knowledge of the danger. For example there is a board that is failing on my deck. It is possible that it could give way leading to someone twisting their ankle or even breaking a bone. Yet I walk on my deck everyday--because I know to avoid stepping on that board until I get around to learning how to fix it and doing so.
Maybe he knew the places where it was more dangerous than well designed and built similar rides, and what to do or not do at those places to minimize the risk?
Surf instructor sends novice who has never surfed before out to surf Teahupoo. In his defense, the instructor was planning on surfing it the same day.
I'm pretty sure you can get involuntary manslaughter for driving recklessly, crashing your car, and killing your passenger. Or failing to maintain your car properly, crashing it due to an avoidable failure, and killing your passenger.
If I'm correct and you can get inv. manslaughter when you're in the same vehicle as the victim, it shouldn't be too hard to prove when the person was only planning to be in the ride later.
(IANAL, though. Legal definitions of those words may not match my intuitive understanding of them...)
The legal definition of recklessness requires that the person know (or should know) that the ride is dangerous. Legally, it is more difficult to prove when that person took actions that suggest they did not think it was dangerous.
To your point about broken safety features:
One could potentially even argue that the brake isn't a safety feature. It could be there to help riders that are scared of going too fast to more easily control their speed, simply for their own enjoyment. I don't think that use of the brake would be required under normal operations and therefore, it could be argued that the brake wasn't a safety feature. I personally don't think it makes sense that a "safety" feature is optional and relies on the rider, but I could be wrong. The designers were certainly negligent in other ways....
Not sure if that follows or if it makes any more sense to you, but legally, its a potential argument.
[0] https://www.wycocourtks.org/uploads/4/4/1/2/4412070/2018-03-...
While in general safety features can require a competent user, e.g. the brakes in your car, in the case of amusement park rides that allow children that does indeed not make sense.
But... I would argue that this is just evidence of substandard design of the speed control system. There is ample evidence of a history of injuries due to excessive speed.
When a safety feature was out of service, they decided to keep running it. That sounds like a director of operations decison.
And much easier case to prove than design deficiency.