good question. if you have first hand knowledge of a candidate's qualifications, it is going to change the interview for sure. but that doesn't mean you don't need to figure out if there is a fit with your team/company.

i don't think focusing on specific details is antagonizing if it is done right.

a great candidate will embrace the opportunity to talk about their experience. it will probably be an awesome conversation for both of us. i will learn something, and they will see their experience in a new light trying to explain to someone else.

a weak candidate will stumble on details of their experience, or will be forced to admit someone else did steps x, y, or z. or that the claim is inflated.