and the police will have a hard time getting to any specific spot. Meeting at 2 or 3 initial spots, then mass marching in all directions with groups of a hundred or so stopping and staying at intersections untill all corners are secured as far as one can see, will not only freeze a city, but with messengers from each corner running to the next four corners will allow for jamming communication and mobility; whereas if theres a strong police presence at a particular place five people from each intersection within 10 blocks can move towards hotspots or move to intercept police movement within minutes, groups can move from spots deemed no longer neccesary etc... 100 intersections blocked
would pretty much shut down any city.
Monitoring police communications is also a must, and with the relay system, the information can be passed over great distances quickly. Cops are morons, and anyone should be embarrased to be out smarted by them.