But whyyyy seat belts?
I'd assume it's because Mystic River Falls has an 82 foot drop; although the deceleration forces at the splashdown would merely throw you into the center of the raft without a restraint, that is definitely be something most parks would want to prevent.
So I've had an evolution of thought on seatbelts, especially after riding Barge's Bilge Rats at IoA - while you can put me squarely in the anti-seatbelts-on-water-rides camp; seatbelts arguably allow for larger, elaborate layouts. This ride, Infinity Falls (SeaWorld), etc. do have seatbelts, but also have massive drops and water feature. So maybe... it's a necessary evil?
Because standing up on the River Rapids might be the single most dangerous thing a guest can do at an amusement park, on par with climbing over fences to retrieve a lost hat. If a jolt sends you tumbling out of the boat, you can quickly end up under it, or between the boat and the trough, or be sucked towards the grates over the water intakes, or sent into the path of the next boat, or caught in machinery, or probably a hundred other awful places you could feasibly be stuck for the rest of your life. Might as well tie the guests down to prevent that from happening, particularly on the largest and wildest rapids attractions.
Preach!One thing I really hope they have on this ride is center console plastic covers - huge godsend with stashing bags and keeping them dry during the ride, and (honestly) reduces the "entry barrier" for folks to jump on a water ride; having to pay for a separate locker fee can often be a deal breaker for hopping onboard.