While this is a policing matter in the first instance, the deeper question is why does this kind of thing happen, and lets face it happen in Dublin.
The decrepit city centre, the open drug dealing, the shoplifting culture, the street and Luas brawls, and this type of mass loutishness. I have no doubt there are instances like this elsewhere in the country but it seems to me a Dublin issue primarily. There is a significant underclass which does not feel part of society.
I blame the parents !