From: Youtube
Updated, 7:58 p.m. | In a tense showdown above the East River, the police arrested about 400 demonstrators from the Occupy Wall Street protests who took to the roadway as they tried to cross the Brooklyn Bridge on Saturday afternoon. The police did not immediately release precise arrest figures, but 
said it was the choice of those marchers that led to the swift 
enforcement. 
“Protesters who used the Brooklyn Bridge walkway were not arrested,” said the head police spokesman, Paul J. Browne. “Those who took over the Brooklyn-bound roadway, and impeded vehicle traffic, were arrested.”
But many protesters said that they thought the police had tricked and trapped them, allowing them onto the bridge and even escorting them across, only to surround them in orange netting after hundreds of them had entered.
Things came to a head shortly after 4 p.m., as the 1,500 or so 
marchers reached the foot of the Brooklyn-bound car lanes of the bridge,
 just east of City Hall.
In their march north from Zuccotti Park in lower Manhattan
 — headquarters for the last two weeks of a protest movement against 
what demonstrators call inequities in the economic system — they had 
stayed on the sidewalks, forming a long column of humanity penned in by 
officers on scooters.
Where the entrance to the bridge narrowed their path, some marchers, 
including organizers, stuck to the generally agreed-upon route and 
headed up onto the wooden walkway that runs between and about 15 feet 
above the bridge’s traffic lanes.
But about 20 others headed for the Brooklyn-bound roadway, said 
Christopher T. Dunn of the New York Civil Liberties Union, who 
accompanied the march. Some of them chanted “take the bridge.” They were
 met by a handful of high-level police supervisors, who blocked the way 
and announced repeatedly through bullhorns that the marchers were 
blocking the roadway and that if they continued to do so, they would be 
subject to arrest.
There were no physical barriers, though, and at one point, the 
marchers began walking up the roadway with the police commanders in 
front of them — seeming, from a distance, as if they were leading the 
way. The Chief of Department Joseph J. Esposito, and a horde of other 
white-shirted commanders, was among them.
