Management - punishment for a previous life?

I read an interview with a manager this week who said that she didn't allow office back-biting to go on and just got people into the same room to sort it out.  She said that normally all parties ended up laughing about it by the end. Really?  I bet once they got back to their desks the smiles are off their faces and they are sticking pins in to wax models of 'the other party'.

All work places have their share of back-biting, and I can see that getting the protagonists to discuss it is good, but surely it depends on the subject matter?   If it is complaining because somebody isn't pulling their weight, or has done something incorrectly, that is totally different to character-assassination on personal grounds.

I do get fed up sometimes with being expected to be the middle-man, and would like to say 'oh for heaven's sake just sort it out between you', but it just wouldn't work in many of the cases. Like the ones that consist of "Grrr, she just walked in the room and I was annoyed, it's the way she puts her bag down!"

I know that there are people who read this who are experienced in such matters in the work place, what do you think?