In Idaho upriver we generally are able to keep 2 per day / 10 per season, but the last two years it has went up to 3per day, 9 in possesion, 40 per season (hatchery fish only), because of better than usual returns. I think I tend to keep alot more than what I need when it's 40, (just about every hatchery fish I catch) than when it's 10 ( I'm not as picky on getting that mounter). I kept 19 last year, giving alot away, and smoking alot. I did not release many hatchery fish during catch and keep. One night last year we took home 4 fish total weight 70+ pounds. I released a 16lb hen on top of that , plus my dad had on 2 other 17-19 pounders near the boat. Thats alot of steelhead.
I don't think any bag limit will limit the amount of time I spend fishing, since I caught and released a few 100 fish last year, plus witnessed about the same. When the catch and release season is open, flyfishers compete with egg roe drifters for fish. People aren't out there to purposely kill fish, but they are there to fish never the less. Im not sure why Idaho allows baitfishing during catch and release, it makes it very difficult for flyfishers.
I don't believe any wild steelhead should be reduced to possession, and do not understand why you can or would keep them further down river. The hatcheries up here only take in about 1200 adults though, split from nov and march. That leaves a bunch of hatchery fish to be caught. So if they are hatchery I say catch' em. I'm not sure if the extra fish per day has an effect on mistakenly killing wild fish or not. It's still pretty rare to catch a 3 fish limit up here, don't know about downriver. If they want to protect wild fish up here I think they should go no bait during the catch and release season for a start, maybe no bait at all, any time of year.