Flash mobs were originally fun, spontaneous events. I got caught in a zombie flash mob in San Francisco once. It was hilarious. There was also a big pillow fight flash mob where 150 people showed up in pajamas and started beating on each other with feather pillows. All in fun until the pillows broke and feathers clogged up the city drainage system. What’s happening now with these “rob mobs” is something entirely different.
Not sure what the concern is for the subways... Might be some flooding in a station or two, but safe transport during the raging storm above. Why state they are closed (hype-ing the sotrm?), when with an observer (presuming he/she is awake) at the front of every train to monitor presence of water, they could just shut down sections as needed.
I don’t know if you would call it a flash mob, but two winters ago in Washington, DC during or after a 24 inch snowfall, about 200 people showed up at 14th and U Sts., NW to have a snowball fight. They were haveing a great time when an off duty policeman showed up and pulled a gun. The crowd began shouting, “You don’t bring a gun to a snowball fight.”