>>epista+(OP)
I feel like some upfront setting of expectations would really, really be helpful here. If you're planning to arrest people after curfew, explain that in clear terms: "Our curfew is at 8pm, so we will start asking groups to disperse at 7:30. At 8pm, no large assemblies will be permitted, and police will begin arresting people in large groups at that time. We understand some people will engage in civil disobedience, and if they are cooperative with the police, they will be arrested peacefully. If any protesters start taking action that endangers police (e.g. throwing bricks or running at police unexpectedly), they will be met with force and arrested. Because it can be difficult for police to determine the perpetrator of violence, additional crowd control tactics such as tear gas may be used, so we strongly encourage you to self-police and prevent any violence towards police. After 8pm there will be a 30 minute grace period for those who are not gathered in groups but are in the process of heading home. At 8:30pm, anyone who remains on the street will be detained."
I think it would really help both in terms of outcomes as well as the perception of police if they gave this kind of clear description of what's going to happen. As it stands now, the curfews aren't enforced with any kind of regularity, so they just cause confusion.