Say you know someone, perhaps in your profession, who you admire - whose skills you would like to be able to do or whose types of creations you wish you could create.
In the training and education industry, I see trainers use each others curriculum, stories, games, and methods ALL THE TIME. Even when the content isn't open source, it gets taken by contract staff and participants who simply go out and do it so that it soon becomes open source - rarely is educational content original or documented to the extent that it truly belongs to someone.
So there is the ownership issue, but there is also the personal issue. All legalities aside, what happens to us when we see someone or something and we try to emulate without understanding the reasoning, history, or theory behind it?
I believe that through this behavior we stop being ourselves and start being a version of ourselves we wish we were. We do it because we want to create the same results we saw them get. Yes, imitation can help us learn and get better results, but if we stop there - copying without improving and making something truly original - we only achieve a light shade of the source, and that makes us appear disingenuous.
There will always be those who are content to peddle carbon copies of things they saw and heard, but as an educator, a learner, the challenge is to steal what is legal and morally conscientious, and to do it for the purpose of building something better.