[dotBen]

As a Brit now living in US, I came here to mention Kettling too. (Kettling is when the police entirely surround a protest group and will not let anyone enter or leave for many many hours).

Unlike the other comment on this sub-thread, I don't see any reason why Kettling wouldn't work here in the US (sadly) if the police used it. The density of the streets in UK doesn't come into it when you consider the Kettling that took place in Oxford Circus, London during May Day riots a few years ago.

I think the issue for Kettling in the US is that police here rely more on aggression and fear of attack (the heavy infantry, as the OP puts it) then strategy and tactical superiority. As the OP observes, this then goes horribly wrong for the Police when they are forced to assert that aggression physically on protestors.

The other issue for Kettling here in US is constitutional rights. In the UK the police will Kettle a crowd for hours - which in real terms mean they will not let you out even if you decide to give up protesting. This is frankly as a punitive action more than anything else. My guess is constitutionally the police might not be able to do this to undetained, unarrested citizens.

[nerfhammer]

In my experiences with NYPD blockades as a passerby they typically forcefully imply rather than directly state you're not allowed through, and if you insist I've always seen them sheepishly give up.

[dotBen]

The whole point with Kettling, which kinda makes it punitive, is that they are 100% clear that you are not leaving the enclosed pen they have created.

Sometimes the kettling can go on for 6+ hrs and even with protestors demanding toilet breaks, water or medical issues from standing up for so long, the police have refused them to leave.

[nerfhammer]

sounds like that would be unlawful here on several levels

[ms4720]

In the US I think that might come under false arrest or illegal imprisonment by the police.

[nerfhammer]

Unlawful detainment, among other things I think.

[pstuart]

They should definitely contact the police about that unlawful behavior.