I do research on particular elites of a particular society and rely heavily on interview data. In one fortuitous dinner, at the table behind me sat three people who are exactly the people I wanted to get access to.
Furthermore, they were discussing something that I am precisely investigating! I was attentive to their conversation (as they were, honestly, speaking very loudly) but by no means eavesdropping and their conversation - if viewed in the context of my work - can prove to be very valuable.
Can I use that data for my work? It does not seem ethical to me. But, if I do not use that data, I know I will be 'deliberately' weakening my research and not being true to what I do now know.
Thoughts? What would you do and what would you suggest I do?