This is a follow-up to this question, which I ask due to debates arising in the comments. While I ask it in the first person to keep things simple, it is not based on a real experience of mine.
One of the students in my course shares a last name with another person, I depend on (say a supervisor or teacher of my own courses). This name is not very common, so I suspect that they are related and I have a conflict of interest.
It is acceptable that I look up the student’s name on the Internet to find out whether they are actually related? I am not talking about an intensive search here, just what is publicly and directly available on social media and similar.
My current thought about this is:
If I do not investigate or find out that they are related, I would report a conflict of interest.
If I find out that there is no connection, there is no conflict of interest and I save all the time of the above step.
If I do nothing, I may be accused of knowing (or suspecting) the connection and having a conflict of interest afterwards. So this is not an option for me.
I am mainly interested in the ethics of the situation. Assume that there are no official rules covering the situation. Some commenters on the question linked above considered this stalking.