At OLCI it's a free for all, so if they opened up row 1 / 2 for Golds, the riff raff can also get in. They will compromise trim for Golds, but no one else, and because OLCI doesn't discriminate the upshot is that all seats being blocked at the front, including to Golds (see my earlier posting) unless they nabbed their seats earlier. And indeed Silvers being seat shifted, even if travelling with Golds!

You can tell when this happens if the front and back of the aircraft look full, but there are some scattered seats two thirds of the way down.