I'd have to say that it depends. There are fisheries that are most definately flossing. Such as the Kenai and Fraser. These are large rivers traveling at high velocity with dirty water. Well at least the fraser is, I've never been to the kenai, but I've seen Bob's video. Baits move fast and even heavy leaders are made almost invisible by the dirty water.

There are also fisheries where the fish voluntarily bite such as Lake Washington and the Harrison River in BC. These seem to be clear water fisheries where the fish have the opportunity to inspect and attack an offering that is presented slowly. Baits of choice being a bare hook behind a flasher or dyed shrimp (Krill) under a float.

It would appear that given the opportunity and right conditions, sockeye will most definately bite. The fact that they are such popular table fare means that opening/waiting for a fishery under favorable conditions may not be feasable. I couldn't imagine even a fraction of those fishing the Fraser crowded into the Harrison, it'd make the Wind look like a zipperlip. A lining fishery may be the least of two evils.