This is just a very sad situation for all involved. I'm sure certain sections of coaster fandom to feel compelled to attribute blame, but as far as I'm concerned no party is at fault here.
Kevin acted in good faith because he had ridden other rides before. Universal followed the correct procedures. Mack had designed a ride that had kept millions of people safe every year.
The rule changes that came from Mack and seemed Draconian make much more sense now, but I feel awful for all those folks that are in the gray area where the risk is incredibly low but are barred from riding this type of ride.
I hope it gives some closure for his loved ones