Coming from the natural sciences, this seems unusual to me (boldface mine):
Many of the things for which journalists and legal scholars have berated Goffman are considered standard practice for sociologists, and most sociologists have found the mainstream criticisms of the book to be baseless. Procedurally, journalists object to the pseudonymity of sources and the destruction of her field notes; sociologists point out that institutional review boards mandate that identities be obscured and that they often require the destruction of field notes that could be subject to subpoena in a criminal investigation. Regarding most of the book’s internal inconsistencies, virtually every single ethnographer I talked to described the enormously difficult logistical problem of how to keep track of pseudonymous notes over years and admitted that if you subjected almost any work in the field to that kind of punitive audit, you would almost certainly come up with similar trivial confusions. This is true of even the most organizationally composed people, of which Goffman is not. She cannot off the top of her head remember which year she finished high school, which year she finished college or which year she spent three months in the hospital after almost being killed on her bike by a bus.
I get why one might destroy your data: there could be incriminating evidence–and that’s not an abstract issue, but one grounded in experience.
Still destroying your data doesn’t sit well.