I think it was my 14th or 15th birthday and I told my grandparents that I wanted to go on a trail ride at a stable about 20 minutes away. She called the place to see if they took reservations and they said no, it was first come first serve, and you can't hold your place in line if you leave. That sounds fair enough so we go and Grandma said I could bring a friend so I wouldn't be alone.
We get there and a group had just left to go onto the trail so we just decided to wait. It's mid-July so it's really hot but we found some shade by the barn and just waited so we wouldn't lose our place in line. While we were waiting a little girl showed up. After her a group of people showed up. The trail riders came back and said they can take 6 people. They ask how many people are in the group and they said 5 and ask if the girl was going alone and she was. They decide to take that group even though we were there first and had waited about a half hour. I walk back to the car and tell Grandma what happened and she got so pissed! She gets out of the car and goes up to them to see what their problem is and they said 'That group of 5 were here earlier but left'. And Grandma said 'Yeah, and they lost their place in line. You told me on the phone it's first come first serve. They were here first!' etc, etc. And they were basically like 'Too bad for you'. So we left.
TL;DR Stable says their policy is first come first serve but take the people that showed up after us on a trail ride.
The day wasn't a total bust, we ended up just going to Ocean City and hanging out at the boardwalk all day.