It's no secret that there has been tensions in the weyrling barracks since Kilaueth's eggs hatched. The two Impressees from the mountains seem to have been becoming increasingly subdued, and it eventually came out that rather than being the instigators of the tension they were actually on the receiving end.
It took a fist fight to bring to light they had had possessions stolen or just plain hidden, their cots had regularly been doused in water (and worse), and they had been bullied into doing the majority of the barracks cleaning on top of everything else.
Weyrlingmaster V'dim's solution was perhaps unorthodox, but it does seem to have calmed things for the time being. Of course the sight of the weyrlings going around physically tied into pairs is an odd one indeed, but it does make punching that little bit harder.