While this sounds good on the surface, much of engineering is pushing boundaries and just because an engineer has a formal education, a license and some simulation software doesn't mean they are going to build something that is safe.

I would trust physical models (aka trial and error) in this case just as much if not more than simulation models.

Turbulent water flow, varying weight/seating positions in a _rubber_ raft, varying friction as the raft bumps the walls, etc all are going to explode the model space. Combined with a general effort to push the envelope and create an exciting ride the basic seat of the pants (high-school) physics is going to set some boundaries on weight/angle/etc but the final details aren't necessarily going to be 100% accurate.

Worse, it wasn't the ride so much as the safety equipment which failed. Having a raft/etc come slightly off the track at the top of a hill like that is probably part of the design. I've been on other slides like that where you leave the surface for a bit only to be caught farther down (its pretty much guaranteed on roller coasters). I can see a PE making the same mistake, the ride is safe, but "just in case" lets throw some netting up to catch anyone so its absolutely impossible for them to be ejected. Hence my comment earlier about how master blaster still has the same kind of netting to this day, despite my own misgivings when I initially saw it years ago.