[Xaccers]

I seem to recall when that actually took place, one of the reasons arrests were not made at the time was that it could have inflamed the situation, which it doesn't take a genius to realise would be a very bad thing.
Now nomadking, could you please explain why you would have found it preferable for the police to turn a reasonably peaceful, if unpleasant, protest into a potential riot rather than gather evidence, track down those who have comitted crimes, and arrest them at a later date?