Class III tubing can be safe!
I used to live about a 1/4 mile up from the water park in Golden right on the rio. We would don wetsuits, helmets, and PFDs, grab a good size inner tube, and hike up to the 1st tunnel and put-in at the nice drop right on the bend and float down through the water park. Late summer thunderstorms produced flows of 1,100 cfs, which made for some great fun and wild times. We never had any mishaps, but a lot of fun. When done thoughtfully, and with proper technique, the whole tubing thing can be a riot! When ya get bored paddling, give it a try . . . .