Re: odd question
Personally I think your within your rights to catch and eat, where legal, but....
IMHO you should also give some thought to the resource too, so if it's a put and take, hatchery supported fishery, keeping fish may have a lot less impact than a fishery based on wild, naturally reproducing fish. In many cases, they just can't take the pressure if most people kept "their" fish.
It's not just fly fishing. Many gear guys do the catch and release thing- many LM bass anglers for one, and many others, including many surf casters here in the NE for striped bass, steelheaders out west that may keep a fish with clipped fins (stocked) but let the wild ones go.
There are whole fisheries based on catch and release, including tarpon and bone fishing in the keys, and many fisheries have bounced back after closures or more restrictive limits, including redfish, striped bass, and many trout streams.
So if you want to keep a few, fine, but just be aware that doing so can have a bigger impact on some fisheries than on others.