In a really small body of water, you can singlehandedly shut down the fishing if you fish it often enough, but it's a temporary thing, and not easy to do, so I wouldn't worry about it. I was the only one allowed to fish a local golf course, and it wasn't like cheating, it was cheating, 20-40 3-8 lb bass every outing, good for practicing, just like a driving or putting range.