How many people have died?

None that I know of. Their safety precautions are top notch.

From the website: SOAR USES THE FALLSTOP® ADVENTURE SAFE LINK SSB® THE SMARTEST AND MOST ADVANCED BELAY SYSTEM FOR AERIAL ADVENTURE PARKS AND HIGH ROPES COURSES! Conventional belay systems in ropes courses and aerial adventure parks allow climbers to voluntarily or involuntarily completely detach themselves from the safety line.   The SAFE LINK SSB® ensures that the climber is never detached from the safety line! Once attached, the interconnected carabiners can only be opened one at a time. My youngest was 7 when he did the entire tower and it had recently rained so some areas were slippery. It is very safe and a whole lot of fun! Go two hours before closing for a reduced rate just to try it out. It's well-lit and you don't have the sun beating down on you. Plenty of time to do nearly everything on the tower.

To my knowledge none. They have some great safety's in place to make sure you can't fall. Once you enter and clamp in there's virtually no way for you to unclamp unless you leave.