I know March 3 is NPC Badge Day and I would love to wear my badge. That day I will be interviewing for graduate school assistantships (including one for Greek life!) and I didn't know if it would be appropriate to wear my badge.
Obviously, I am proud of my affiliation, but I do not want the other interviewers to see me as just interested in Greek life and then not consider me for their positions.
Definitely I would wear it in the interview for greek life. The fact that you can bring up that you're aware it is NPC Badge Day if they ask is a huge plus. In the other interviews I'd keep it off. There is a minimal chance it could help you but a significant chance it might confuse (or even offend) a non-greek interviewer.
I had my Greek interview second today, so I put my badge on after the first one was done. I looked around and noticed many people, interviewers and prospective students had their badges on (including guys!), so I just left it on for the rest of the day!
I hope you did well and wearing your badge was a good idea.