Too many things break to ride alone. Small lakes with minimal dangerous animals are okay.
You never know when a small part might fail. List ive seen personally is bilge pumps, exhaust outlet, overheat, broken return spring, water ingestion, fouled plugs, just to name a few. All of these things took out what seemed to be erfectly working machines.
On 2 occasions, the exhaust outlet nd the bilge failure, the macjines were almost lost. The exqust outlet failure put the boat on the bottom in less thn 5 minutes 2ith foam. Saved it with a tow rope. Alone it and poasibly the rider would be lost. The brokem return sping got pretty harry too, it was an older ski without a lanyard, but i hit the stop when i felt the throttle go limp, otherwise thay boat would have been a few milesmout into the gulf and i would have been a bobber. Broken return springs happen.