They do not share the prize.
I know they don’t share but the average won amount is quite small. Doesn’t seem worth putting any effort in it.
A good way to control people with nothing to do otherwise. I doubt if anyone quits their job to go looking. Bury a canister with a $100 bill in it and the winner reports the serial # on the bill to collect the rest. That way the organizers can put an end to it. Just watch all the ‘disabled’ people suddenly go into action while still collecting their disability checks.