This sort of thing really pushes my buttons. I fish Glenelg jetty quite a bit and see similar things happening. There is a bloke that is seen as a local garfish guru, but I see him regularly slip small fish into his white bucket of shame. He knows what he's doing, he doesn't measure them and just slyly slips them into the bucket.
Just from my own observations, at Glenelg, most people are doing the right thing measuring crabs. But some "old timers" are taking the mickey with the fish they are keeping.