NYPD did this, (kettling, imprisonment in vans with no bathroom breaks, and more I can’t remember), in 2004 during the Republican National Convention. They were sued and eventually lost. Lots of tax payer money has been lost over the years to law suits due to NYPD heavy handedness, politics, escalation tactics. Does anyone remember the 2008 body slamming that briefly hit the mainstream news and then vanished?

(2014) https://www.nyclu.org/en/press-releases/victory-unlawful-mass-arrest-during-2004-rnc-largest-protest-settlement-history

(2018) https://gothamist.com/news/10-years-ago-a-cop-bodyslammed-a-cyclist-during-critical-mass-ride

(2008) https://www.cnn.com/2008/CRIME/12/17/youtube.cyclist.cop/index.html