I agree with asking your child to wait if another child is using the ride. If another parent puts money in and DD wants to go on, we'll let her know that she needs to wait until the other child is done. Sometimes the parent will offer (in which case I'll offer to pay for another ride after), otherwise no biggie, DD learns about waiting and sharing and being social, and then she gets to ride anyway. I don't know, I don't see the big deal myself. Kids like rides, kids generally enjoy playing with other kids, and it's $2. I figure if I'm paying for the ride, it may as well be full. The only gripe I have is an older child being silly and scaring the younger ones, in which case I'll nicely remind them that there are little kids on the ride and to be careful. I think learning to be social and play and share, and learning to be patient and wait are equally important and I think both lessons gain easily be gained in the sane situation.