system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5 What is kettling, and why do police use it against violent protests?

I saw a news article mention something called kettle zones?
gpt
Kettling is a police tactic designed to solve a specific problem. Often, people will take advantage of protests to start riots. When they do, small groups of criminals break off and loot, steal, or attack people or buildings. Once a crowd is spread out and the tension is high, these things generally happen.

So the police came up with a way to herd an entire protest into an encirclable space, like a bridge or a low-value street or park. They contain everyone, that way there is no broader damage. In principle, there is a police checkpoint where you can pass to leave the protest, but in practice the police will not let you out unless they are 100% sure that you aren't going to commit any crimes on the way out - so in effect, basically no one is let out. After 3-6 hours, the police feel everyone will be too exhausted, hungry, thirsty and desperate to pee to cause trouble and will quickly disperse.

It's been a practice that's faced sharp criticism. In a legal sense, it's detention without cause - for anyone in the area, whether they were looters waiting to happen, individuals expressing their desire for political change through peaceful protest, or just people who happened to be nearby. It's also viewed as a violent counter to peaceful protest, a means of discouraging mass protests against the policies of the state. Plus, if things do turn violent and you didn't want to be involved, you could be stuck in a bad situation and possibly seriously hurt.

Yet, and this is important, we do not have an alternative to kettling once a protest gets angry enough to bring out the looters and rioters. We can prevent ourselves from needing it if police and protesters can view each other as friends, but that's difficult to achieve on both ends. Occupy Wallstreet in New York was a great example of a protest movement that was police-friendly, and the police handled it in a perfect textbook way in New York. At the same time, the London equivalent turned quickly violent due to differences both in the protest culture and the police culture on protest.

What are your thoughts? What can we do to prevent stores being lit on fire and cars being overturned during protests?