If no one is policing people squatting on balls they did not reserve, then the reservation process is useless - so keep the online payment and eliminate the reservation process.
First Come First Served with online payment.

I've been chartering in BVI since the 90's.
If you wanted to make sure you got a ball, you got there early.

Now, you get there and someone is squatting on your ball - and the rest are all reserved.
This is a solution causing a problem.

Hey, Boaty Ball: Eliminate reservations and keep online payment.