I've fished trout parks a lot, and I still just don't get the mentality of crowding in on somebody. Sure, it can get tight at times, but I'm going to be trying to work with the people around me rather than go on the offensive. Just like my mother Saint Lee would have wanted me to.
In the particular case above, I would likely try chatting the guy up for a bit, then maybe drop a hint. That way I'm a friendly guy to him, not a competitor. If he didn't get the message I sure wouldn't stew about it and let it ruin my day.