How confidential are your interviews? Many would reply that their interviews were entirely confidential: notes are always filed away afterwards and the discussion is never divulged to others.
But what about your interviewees? If you believe that they reciprocate your confidentiality, then prepare yourself for a shock. Many openly share their interviews with others, not only questions asked, but even exercises or presentation topics as well. Within hours, your process might be openly available online for all to see.