The idea is that if the tiller person gets thrown out in surf the boat is still running and the other person in the boat can take over quickly and pick up his mate. Ie no dead engine in the surf zone .They remove the normal kill cord switch and fit a throttle return spring .
In reality it never seems to work that way , the lifeguards also agree , the second person /passenger is almost always the one thrown out or both if its like the picture shown
Even a fit lifeguard can't swim fast enough to catch a sib ticking over in gear in surf . The problem is the throttle on tiller steer outboards is usually quite stiff as it doesn't just operate a carb slide like a motorbike set up , add days on the beach ,salt, sand and no maintenance and the throttle just stays where its left , usually wide open .
I believe Its only luck that we haven't seen an out of control circling lifeguard sib on a beach yet. Although i guess the next wave would probably soon disable an empty boat and if its the crew are thrown out the boat is usually capsized too wich tends to stop the motor quite quick .
I expect It also costs in drowned engines going under while revving