[Mikman]

That movie parodied those kinds of roles, so it's not really the same thing. But in a serious movie, I believe that it's mostly wrong. I really dislike when a mixed-race person plays a single-race person, because that implies the continuation of archaic "one-drop rule" attitudes, which have no place in modern society.

As for gender change, I dislike it because it seems like tokenism to me, although I dislike it less if the character is minor or the gender isn't important to his/her persona.