i think it will also depend on the financial situation of a person. i do not speak for myself by the way.it is logical that if you are in a financial bad situation, its tempting to keep funds that you accidentally receive, because it is not a bank transfer but crypto, which gives much more anonymity. the sender should be more careful it think. but that is an ethical discussion.
well, probably most people will say that they are going to return ethereum which they feel is not theirs in their wallet. however, in reality, it depends on the circumstances. I am pretty sure that some people would prefer to use it because we never know what is in someone's heart.