If what they are doing is contrary to the law I may say something and discuss it with them, very carefully.
Was down at Brownsville Bar the other day, lots of anglers out despite the regs being what they are. An older couple hooked a wild trout and beached it. One of the regulars walked over and told them it wasn't legal to keep. The couple didn't seem to understand due to accidental ignorance, willful ignorance, or a language barrier, so the angler walked over, unhooked the fish from their line, and released it while the couple stood by.
It was uncomfortable to watch, though I'm glad the regular had the willingness to step in. He took the time afterwards to explain the regs to them, and also drew some pictures in the sand about ID'ing fish. He was friendly about it all, despite the situation being super awkward. The couple didn't seem to have any idea about fish ID'ing in the Fraser, or what was legal to keep. They caught a 4" sole a few minutes later and carried it over to him to ask what it was.
Good work random guy! I think that most people (myself included) just don't have the appetite to get involved with strangers who may or may not be receptive to the message being conveyed.
(If that was you at Brownsville, send me a PM and I'll introduce myself if I see you again
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