Long ago, I ran part of the backend systems for a contractor that had a variety of state and other parks. One set of islands on a lake in particular were very important to a number of people for various reasons.
Specific weekends were in particularly high demand, and people discovered gaps in the booking and rescheduling policies that would allow them to reserve the spot at a different time, then do multiple re-books. IIRC, they would spend about $500 in re-booking fees and would have to coordinate re-booking in multiple specific, inconvenient time windows. (Part of it involved a window where the phone system would accept changes before the online system)
Somebody figured it out, and it escalated to the point where the legislature was investigating it and one of the VPs had to testify to a committee.
Edit: This seems to explain it - https://news.ycombinator.com/item?id=21625871
My thoughts exactly.