It is a truth undeniable. Large crowds are there to demonstrate the strength of feeling, and large crowds are dangerous.

You can blame all the agitators you want (and they will be there) but it is all to easy to make a large crowd look like a brawl. Don't forget there are those that actually like fighting, being hurt is a badge of office. And large crowds hide miscreants all to easily.

Have your video phones ready at all times, and let people know you are using them. (put them on a loop around your wrist or waist or they will get knocked and dropped). And use them on the crowd not the police, the enemy lurks within. The agitators will move away from video evidence or try to damage it. Either way - they are revealed. If video phones are universally visible there is nowhere to hide.

Vigilence is your protection, then you can get on with the job in hand - showing your strength of feeling.