To build on Uke's post about Paul Berliner, that kind of ethical question has been a common topic of debate amongst folklorists and ethnomusicologists here in the U.S. What is appropriate to publish? Some folklorists, when publishing sacred songs or texts, strategically change a few small elements in consultation with their informants, so as to alter the sacred nature of the piece. Sometimes just omitting a line or reversing the order of lines is sufficient, but sometimes more drastic measures are taken.
When I was very new to academia I attended a conference of the California Folklore Society at which the folklorist Barre Toelken was giving the keynote about his experiences with his informant "Yellowman," a Dineh (Navajo) storyteller and "medicine man." Barre had been collecting songs and stories from Yellowman for years, but out of respect for the cultural context of these stories, he chose to publish very few of them. When Yellowman died, Barre was faced with a difficult dilemma for a folklorist. Many of the stories and songs had specific uses, were tied to specific ceremonies, specific times of year, times of day, etc... and Yellowman was concerned that if these things were printed and they were subsequently performed out of their proper context, particularly if the recordings of his voice were played outside of the proper context, that this would cause problems––spiritual problems of a cosmic nature. He literally thought that "someone could get hurt." Now Toelken could have made good money from publishing these stories or releasing the recordings, instead, he turned all the material he had collected from Yellowman over to Yellowman's family, and they destroyed the whole kit and kaboodle. Now, when Toelken announced this at the folklore conference, people went nuts. Some were berating him for destroying this valuable material that should be considered property of all Americans, a national treasure, and should be kept safely in the Library of Congress or some such receptacle. Many others, however, myself included, felt that this was a bold and noble assertion of Yellowman's right of ownership. It was not up to Barre to decide what should become of Yellowman's material, ultimately it was up to the "source" to decide.
This has been something I have tried to follow in my own fieldwork and to teach to my students. That being collectors does not make us the owners of what we collect, merely the stewards. We must always, ALWAYS, provide copies of recordings to the informants who make the recordings, and to their families. The informants always have the right to place conditions on the usage of their material. And we must always be cognizant of the impact we have on the people and communities with whom we engage. We fieldworkers have to impose ourselves on people, and in that process we can change those peoples' lives, which is why we must be very careful and must always listen to everything our informants tell us, not just that which we want to hear.