Close to a dozen protestors hung from a tall Portland bridge (St John's Bridge) in a fairly successful attempt to block the passage of an oil-company ship that was headed to the Arctic for oil exploration.
Being a very liberal/progressive city, naturally the cops didn't do much to dissuade the protestors from continuing their protests. (one enthusiastic person with a scoped .22 caliber rifle could have done far more to discourage the event than the police did.)
By the time I paid attention to it, on television, I noticed that a Portland Fire truck (?) was being used to block the passage of all four lanes of traffic across the bridge, despite the fact that the protestors themselves were not even arguably blocking that traffic.
It suddenly occurred to me that far from being opposed to the protestors, the cops were actually ASSISTING the protestors: The cops were doing that (blocking the traffic) which would have been illegal for the protestors themselves to do; effectively, the protestors were acting as a justification and impetus for the police to further obstruct and inconvenience the public.
I am not suggesting that the average, rank-and-file cop would have recognized what was really going on, unless it was pointed out. A word from a high official, say the mayor, to the Chief of Police, "Looks like an unsafe situation! You'd better block of traffic over the bridge with a fire-truck!", might at least arguably have looked like a plausible tactic. But it still could have been a coordinated (informally) arrangement. With plausible deniability, of course!