Of course they can.
Most of the dissidents in this country are well known and tracked as closely as if they had implanted GPS transmitters.
The same people show up at every protest, get arrested and let go by every city they visit by liberal judges. A phone call from Washington, a hint of a under cover arrangement, and a get out of jail free card.
Dozens if not hundreds of arrests, and they just walk.
Why? The Feds get more information from them running around loose than they would if they were in jail.