That's the title of a useful article by Lawrence A. Kane. It contains valuable insights into crowd behavior, and how to deal with them.
The crowd mindset of being one face among hundreds can be a very dangerous thing. It's quite easy to get caught up in the fray, not truly thinking about what is going on. It can even be a lot of fun for those involved, particularly when they don't consider the consequences. For some, it's an adrenaline rush that rivals any amusement park ride. Consequently, things can get out of hand pretty quickly. When they do, they are very difficult to stop, even once law enforcement officers arrive to take control.
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A panicked crowd is just as dangerous, if not more so, than a riotous mob. When someone believes that there is imminent danger and flees in panic, his or her actions can spark fear in others who act accordingly. This fear can be initiated by actions from others such as setting off a bomb or discharging a firearm, and may be exacerbated by environmental factors such as flooding, smoke, fire, or tear gas. It gets even worse if there are limited escape routes, blocked exits, or other factors that lead to desperation where people begin fighting each other to clear a path so that they can get away. Think about all the people who have been crushed to death at nightclubs, concerts, or sporting events when crowds got out of control.
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If you are a civilian concerned about self-defense then your goal will be to escape to safety, remaining as anonymous and avoiding as much of the conflict as possible in the process. You will move away from the danger.
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There is a huge difference between a highly-spirited crowd of shoppers, a restless throng teetering on the edge of violence, and a riotous mob, one that most anyone actively paying attention can sense. As things begin to turn ugly, don't hang around to watch no matter how fascinating it might be. Leave as quickly and quietly as possible. Plan your exit route to minimize contact with others, even if it means taking the “long way” around the scene. Slip through gaps between others rather than shoving people out of your way to the extent practicable.
If you are forced to fight you may attract undue attention and quickly find yourself facing multiple opponents who want to beat you down or law enforcement officers who don't realize that you are the good guy. If you are knocked to the ground or stumble and fall you may very well be trampled. If you have to fight you will lose valuable time and there is no guarantee that you will survive the encounter, so rather than engaging opponents directly, attempt to deflect or redirect anyone who tries to slow your escape using open-hand techniques.
There's more at the link.
In these troubled times, where riots and urban unrest are so prevalent, this sort of information may save your life. Read, remember, and discuss with your family members. It might come in handy.