Doc -
Interesting question as with most issues in the fisheries world there isn't a black and white answer.

For me it would depend on how well the out basin hatchery program is segregated from the wild population. In the situation where the hatchery program is segregated the bonk or releasing the unspawned hatchery fish would make virtually no difference to the productivity of the wild population unless the keeping of the hatchery fish reduces the number of wild fish the angler catch.

For the situation where the hatchrey and wild populations are poorly segregated then bonking and using the fish in some fashion would be the choice. For me the situation of hatchery program where wild broddstock demands that all the hatchery fish be removed unless the wild population is in such door shape that the hatchery program is rescue program. In at least the areas that I'm familar with it is virtually impossible to develop properly intregrated hatchery program for steelhead using wild brood stock - unable to incorprate the full diversity of the wild population in the brood stock.

In the basin (the Skagit) where ISO's pictured kelt came from the hatchery program is so well segregated from the wild fish that it represents very little threat to the wild population (at least in hatchery/wild interactions on the spawning grounds). In fact it may well be that those natural spanwing hatchery fish represent less of threat to the wild steelhead productivity of the basin than the current CnR fishery.

Intersting discussion -
Curt