The best way to avoid traders camping there is to remove all the profitable routes that go through or passes near NY.
For example, if you are caught in the middle of the route between kurile and cambridge, you will have to make a 30 min run to reach NY.
(If you find any mistake in my English, please let me know via a PM)
(Really, I speak terrible English, so please, tell me if I make mistakes. I'd like to improve it a bit )