The beach balls never served any real purpose, it seemed like they served more as a distraction than anything else.
Once you're let onto the platform, everyone runs for the balls, and they are so big, once you're in the tire, you can't get one. Once the tires are in motion, you'd see people reaching for them & unable to pick them up.
So after the first toss, if someone didn't catch it was over with.
Plus it was weird if you didn't know anyone else riding, you'd been throwing large beach balls at random people.
I threw my beach ball toward the wall because it was just getting in the way.
Farewell large beach balls...
According to what my brother heard in a History of Disneyland class he took this summer, the beach balls weren't originally part of the attraction and were added at the last minute as a deterrant to keep people from going too fast (if you're good and don't hit anything, you can get those tires to around 15 MPH). I guess they didn't quite work out. Other fun things he learned about that attraction include that it functions fine in the rain, but the fans reduce visibility to about 12 inches, and that if you put one of those parachute army men on it before turning it on, the fans are strong enough to launch the parachute man to the top of Tower of Terror.
Plus there wasn't any objective to throwing them, it was just random.
Walt Disney World's Magic Kingdom
Disney's Animal Kingdom
Disney's Hollywood Studios
Disney California Adventure
Universal Studios Florida
Universal's Islands of Adventure
Universal Studios Hollywood