Apparently the shoulder strap or harness had a Velcro closure which came loose. This happened to an adult man earlier this year and he had to hang on with all his strength to stay in the float or raft in which he was riding.
Velcro is a quick connect / disconnect so more riders = more $$
That will change if the ride stays open.
Really, velcro? That’s gonna be a huge lawsuit then.
It’s standard on roller coaster rides nowadays for the harnesses to lock in place without any straps that can come loose, or if there is a strap, it’s secured with a solid latch like on a seatbelt. I would guess they can’t use all the same materials for water rides, due to corrosion issues, but velcro is about the stupidest design choice I could imagine.