My question has to do with deception, and concerns whether or not a person needs to change his name. (I'm not thinking of a specific person, and don't require a psak).
For the sake of an argument, what happens if a man with the surname of Cohen marries a non-Jewish lady and has a son, who grows up and marries a Jewish lady, also having a boy. This boy is Jewish, since his mother is Jewish, and he has the surname of Cohen, since his father's surname is Cohen, but he is not himself a kohen since his father wasn't one.
In such a situation, would it be considered necessary for him to change his name, lest people mistake him or his subsequent male descendants for kohanim?