Plagiarism is using someone else research, papers or ideas without given the due credit for their work.
Most people understand what plagiarism is but do not fully get what is means.
Almost every know that repeating someone else's words without acknowledging them is plagiarism but few understand using someone else ideas and even copying their research is considered plagiarism (Indiana University, 2008).
Yes by all means plagiarism is unethical, just the idea of using someone else work should be ethically wrong to everyone.
If you did work and someone else got the credit you be both hurt and angry so way would you do it to anyone else.
We need to as humans to realize that taking anything that is not ours or we do not have permission to use or at least give credit to the creator is wrong both ethically and morally.
The only time I think I would be at a wonder about this would be having an idea that is openly talked about that I would write down.
What I mean is I would wonder if using statements in everyday talks would need site as a source, this being due to fact that many people say things daily that give us an idea to write about and do we have to give them credit.
I would think not just a normal talk that's gives you an idea would not need cited unless you use direct quotes.
I would say to distinguish between citing and not citing a source you would have to think is what I'm writing my idea totally or did this person give me information I must use in my paper.
If they just gave me the idea and I do all the research and write using my own words I would feel I did not have to cite.
But if I use any words they told me or ideas they had about my topic I must cited them.
Word for word copying of anyone else writes or statements with citing are plagiarism (University of Minnesota, 2008).
So to conclude if at doubt then cite it does not hurt you at all and may give someone else credit they can benefit from.
And help them to go further in their field as you well in yours.