I think that morning meetings can be very effective.  I was in a class that had done them at the beginning of the year, and the students were all kind to each other, with the exception of the occasional 3rd grade tiff.  However, this teacher had stopped doing the meetings because it was hard to keep them short.  I think that the possible benefits are astounding, but some of the things that children say I'm afraid I wouldn't think fast enough to be able to react appropriately.  However, I do know that we always get better with practice.