What reason would that be? Just to keep the crowd away?
That and fishing isn't great. The winter run this year wasn't good, plus the water was crazy high. As of last week, 391 springers had returned compared to roughly 2400 by the same time last year. Again, water conditions are high (but have dropped a bit).
But, even if fishing was good, those catching fish probably don't want an extra thousand people to compete with, and they therefore don't post reports on the interwebz to make sure their fishing experience is worse the next time they go fishing.
I don't fish the terminal areas, so I can't help with your original question. But I can say that barrier wasn't busy last week, which tells me the springer fishing at the dam isn't good yet. Can't speak to the winters at BC.