Lesbo Prof has some interesting recommendations. Here is the part I liked the best:
Second, don’t play “get the candidate.” While a spirited discussion about a candidate’s research is exciting and fun, and can show a candidate that you are intellectually vital as a school, nothing is more of a turnoff than audience members who need to show that they are smarter than the candidate. This is especially embarrassing when the candidate has just finished his/her degree and the obnoxious faculty are senior people. Grow up, okay?! Be clear about this issue with doctoral students, as well, for they sometimes want to show their intelligence by pointing out mistakes by the candidate. I was never prouder of my colleagues than when they humored one candidate whose research was a nightmare; they asked easy questions, smiled and nodded, and then agreed privately after she left that the decision to bring her to campus had been a big mistake. There was no need to embarrass the candidate; she did that all by herself. I explained this to our doctoral students, who were aghast by the presentation and the lack of critique. Sometimes good judgement is more important than proving you are the smartest person in the room.
Most of the folks on my faculty are very nice and would never do this, thank goodness. But once in a while there is an asshole eruption. If damage control is attempted later, it often entails reassuring a candidate that the offending party is a jerk to everyone, and/or not taken very seriously by anybody else. Which I think is one more excellent reason not to play Stump the Candidate during a job talk.