I had an idea of how to handle a flash mob, at least in a city street like this — skunks. If you can get the kids sprayed with skunk juice, it would be easy to identify them as they all tried to run away.
You could have a spray gun with a good quality stain, and spray the mob. Then you’d mark up their clothing at least. And they’d all be pretty upset at having their clothes damaged.
But we’d need vigilantes to do this, so the store owners can’t be targeted for retaliation. I think some smart young kids who know how to use social media, and therefore can get wind of the flash mobs, armed with pump-pressure sprayers.
Of course, I think it would be fun as well to stake out places in higher floors, and shoot them all with paintball guns.
Imagine a flash mob, and then 20 guys rise up on the roof with overcranked airsoft guns and paintball guns, and unleash a few thousand rounds.
Violent packs of animals should be dealt with superior firepower. It makes "retaliation" less likely when they soon realize there are exponentially less feral animals.
Plus it stimulates the teddy bear and candle business when they turn telephone poles outside into shrines.