Catching Elephant is a theme by Andy Taylor
When protesters fail to remain in the designated protest area, they can be cited for trespassing and/or impeding the flow of traffic.
When protesters violate noise ordinances, time restrictions, or assemble without a permit, they may be cited for disturbing the peace.
When protestors act in an unruly manner or impede sidewalks, they may be cited for disorderly conduct.
But when protesters fail to follow orders given by law enforcement, they almost always earn themselves a protest arrest.
Regardless of whether you like the outcome, for decades these sorts of laws and limitations have been approved by the courts. As such, they are enforceable statutes, meaning that a protest arrest based on their violation is wholly within the law.
(Source: blogs.findlaw.com)