I think there's a big and very important difference between simply having a fetish and actually indulging in it. The latter is really where ethics and legality come in. Acting on fetishes/kinks is where the motto "safe, sane, consensual" should be applied. Obviously that term is highly subjective and open to interpretation, but a good rule of thumb is to keep all activity between consenting human adults.

I hope that helps answer your question.

Very interesting topic, btw. I'm eager to hear others' thoughts on the subject.