"Law & Order and the Public Interest. We may disclose your information to third parties if we determine that such disclosure is reasonably necessary to: (a) comply with any applicable law, regulation, legal process, or appropriate government request; (b) protect any person from death or serious bodily injury; (c) prevent fraud or abuse of Dropbox or our users; (d) protect Dropbox’s rights, property, safety, or interest; or (e) perform a task carried out in the public interest."
I would assume that this research fell under the "task carried out in the public interest" clause.