I think that it's perfectly ethical to appreciate and play music that others have produced. It's unethical to hoard it as if if were some rare treasure that only an elite can enjoy. The wishes of the creators and so-called "owners" of the tradition surely would include having their output enjoyed and appreciated otherwise why bother to do it? The implication is that the "outsider" is not entitled to participate in the enjoyment of recreating the music of any given culture.

Where it becomes unethical is when credit is not attributed and a sensitivity to the music learned is not respected and observed.

Frank