I'm not one to get too wrapped up in how people are fishing and what they're honestly targeting, but I have a couple thoughts/comments on the guys fishing eggs. I spent a few days bobbing around near the pump houses last week. I saw pretty light crowding for the most part. The line of bank anglers at the hole next to the old farm house were mostly fishing eggs, and (from what I saw) were catching almost entirely jacks. I did see an adult coho or two caught. I'm sure, considering the sheer numbers of kings staging in that part of the river, that they are getting an adult chinook every so often as well, but I personally didn't see any of those caught, so I doubt they're doing much damage.
The guides, on the other hand (as well as a few locals who primarily fish eggs anyway), are probably killing some kings. The coho fishing has been very hit and miss (mostly misses), and being under constant (if unspoken) pressure to put clients on fish, some of the guides seem to be running eggs to give their clients the best possible odds of hooking something. From talking to a couple of them, I learned that they were getting a coho or two for each client. That's certainly a lot better than I did fishing spinners and jigs in the same water, which I suppose validates their strategy from a productivity standpoint. Still... I have to think they've had more than a handful of wild kings swallow those eggs, especially considering the spots they were focusing on.
If we're serious about reducing the chinook impact (which is what usually determines our opportunity), we probably should take a serious look at the impacts associated with allowing anglers targeting coho to fish eggs in the tidal Chehalis. There's no doubt that eggs are the most proven bait/lure out there, but when they are the overwhelming favorite presentation for a species we're trying NOT to catch, perhaps we should use something different.
As has been said, many times and many ways, the coho fishing is pretty tough for the most part.