We reserved a boaty ball at Anegada this past Tuesday. This was our first experience using boaty ball. Got up at 6:30am and was able to reserve ball #3. Left Leverick and took our time knowing that we had our mooring reserved for the night. We arrived around 1:00pm to find a Moorings boat on our ball. We told the people on the boat that we had reserved the ball and could they please leave. They replied that they had the ball and they were trying to reserve it. I again told them that we had already reserved it. They did not respond but the captain got up and walked back to the helm. We proceeded to circle back around so we could pick up the ball once they released it. When we arrived at their stern everyone on their boat except one person went below. I asked them again to leave and that we had reserved the ball. He said he was sitting on our ball hoping and waiting for another FCFS ball to open up so he could move. We again asked him to leave and he just stared at us. We then threatened to cut their mooring lines so we could take our reserved ball, we would not had done that but we felt that was the only way to get them to leave. They then proceeded to release the ball and we were able to tie up. Unfortunately I did not get the name of the boat. Hopefully the Moorings will read this post and have a better discussion with their charter groups on how Boaty Ball works.