Police and the fucking army abused that a lot during those times, btw. There are a number of videos of police detaining, then releasing specific black blocs, or being suspiciously non-violent. Not to mention the many times cops were caught planting evidence, one I recall seeing was with 3 cops searching a backpack, one of them turned it upside down to see if anything would fall out of it, meanwhile another cop stealthily dropped a bunch of fireworks and used that as proof to arrest the person.