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Similar police weaponization has been used to prevent U.S. trucker protests (following the earlier Canada trucker protests) from entering Washington DC.
The police have observers, and block beltway exits into Washington when truckers attempt to enter the city. The Washington DC authorities used it as an excuse to re-construct the "Camp Pelosi", i.e. military fortification of Washington DC the Democrats set up after Jan 6 2021.

The police blocked beltway highway exits into Washington DC when truckers approached the city. But some got in anyway. Although the larger and more successful part of the protest occurred in multiple cities in the previous weeks, as thousands of truckers made their way across the country, beginning in L.A., and ending in Washington DC.

https://www.cairco.org/news/dc-trucker-convoy-demanding-end-biden-regime-covid-policies.

Predictably, DC police, and police in surrounding Democrat-ruled states, did everything they could to intimidate and prevent the peaceful protests.
Protests they would have encouraged if Black Lives Matter or Antifa were burning and looting their cities nationwide, as they did in the summer and fall of 2020.