Watching TSN games through GameCentre and watching TSN3 through TSNGo are two different things. The games through TSNGo are still region locked, the games through GameCentre are not (except, apparently, your example of watching TSN in the Jets region through GameCentre, which makes sense, because you'd be able to watch on TSN3 anyways).
You weren't trying to watch last Friday's game against Chicago on TSNGo, were you? It wasn't streaming due to it being on nationally in the US, from what I heard. I've seen that happen twice this year.