Hello again, got the Honeydo's out of the way. Anyway, my point being for the above, the summer-run fishing is slow at best so I would welcome a spring jack to the fishbox. Also, I have the similar belief that the liberal limits for jacks are because of the reasons Smilesforyou highlighted. Needless to say, they are quite tasty also.
Fish and Wildlife is definitely not promoting a C&R season for these fish. Like I mentioned earlier, if you are hooking AND LANDING the Hoh's native springers consistently, you are targeting them. I use 8lb leaders while driftfishing and 12lb for plugs during the summer for the peninsula's metalheads. My Friday partner and I took three trips in June, before they reopened the river for springers, for summer-run steelhead. On all three trips we were the only boat on the river. We managed to land two clipped summer-runs and a bunch of native "others" (spawners, chrome winter(?) jacks, and one low-teens hen springer(?) that battled me hard). Yes, we incidently hooked one springer. "It" was sitting in the Allen Bar tailout. Yes, have hooked summer-runs here before, but definitely not your average springer hole on this river. I say "It" because neither of us got a close look. All I saw was a thick back come up and reflect the sun. It was a chromey-purple flash, indicative of a fresh springer. In any case it snapped the 12lb Maxima like thread and sent that Bloody Mary to Tadpolly heaven. From my experience the typical Hoh springer is slightly over twenty pounds and is always pissed-off when you set the hook, conversely the typical Hoh summer-run brat is about six pounds. So If I'm a fish cop I'd probably give guys running 20lb or more a ticket.