All part of why they want to have facial recognition cameras everywhere, and the po-po are wanting to start integrating into private security systems. What they want, and are indeed pursuing, is a fully integrated system where people and vehicles are continuously being scanned. And it won't just be for targeted searches either. Once a person or vehicle's signature is established, they will build histories of everywhere they go, tracking from one camera to another. They'll start off with stuff like this, obnoxious protesters, and if they're of a leftist bent even better. That sells better with the Lore & Order wing of conservatism.
The total surveillance state is becoming a reality, where literally everything a person does at every moment is being logged and recorded. And when you get a plethora of historical data like that, how easy will it be to seed it with outright fabrications if they so desire? It will be so compartmentalized that one hand of the state won't even know the other hand seeded the data, so it won't even depend on a sinister conspiracy across every agency.
Sorry for taking a bit of a different tangent on this story, it just all seems connected to me. They want to make protest into a pseudo-crime in and of itself, and create a chilling effect of the "Oh don't do that, you'll just end up on their lists" variety.