I'm a senior software developer and I often get asked to conduct interviews for junior developers alongside my manager.
He generally gives me free rein to ask whatever questions we need to help judge a candidate's skills and personality. But he has a set of 'red line' questions that disqualify a candidate if they get them wrong.
These are questions like, "Are you planning any long trips abroad in the next few months?" or "Do you write any blogs or do programming outside of work?"
We have to continue the interview as normal and inform the candidate afterwards that we have decided not to continue with their application. It doesn't make sense to continue an interview for the sake of completion.
Would it be unprofessional to tell the candidate during the interview that we won't be continuing with their application?