Todd -
There were no summer fish below Sunset on the South Fork however there were (and still are a few some really rainbows above the falls.
The only summer fish were in the upper North Fork Skykomish.

There probably is some wild rainbow genes floating around in those SF summers. Does that make a difference? - you tell me.

Sparky -
Another example just for fun.
Some of the hatchery summer steelhead have successfully spawned in the Green River (King County) and there are now some wild summer steelhead returning to the Green. Prior to the moratorium folks were allowed to harvest those fish - much like your Sol Duc springs. Is it right to protect those fish.

The point of course is that fisheries management is rarely black and white issues and a one size fits all management has the potential to bite one in the rear.

Tight lines
S malma