When Tristan Anderson, now 38, was living illegally in the trees at the University of California, Berkeley, to protest the administration's ultimately successful bid to cut them down to build a sports training center, life was good.

For 21 months, Berkeley's tree sitters happily fouled their nests with little interference from the authorities. Their biggest fear was falling. When Berkeley finally erected barbed-wire fences and began to shine spotlights on the canopy campers, the tree-huggers complained that UC had turned their grove into "Guantanamo." UC retaliated by giving the tree sitters energy bars.

In June 2008, Anderson, who goes by the name "Cricket," was arrested and charged with trespassing and violating a court order -- and still he was able to chat happily with reporters.

Segue to the West Bank last week. Anderson had joined pro-Palestinian protesters in the village of Naalin, where he was seriously wounded when an Israeli-fired tear gas canister hit him in the head. Fellow activists said the attack was unprovoked. The Israeli Defense Forces said they were reacting to rock-throwing demonstrators. Whatever happened, Anderson found out in the worst way that political protest outside the Bay Area isn't all energy bars and catch and release.

Back in the Bay Area, Anderson's fellow peace activists could have used the awful occasion of Anderson's situation to contemplate how wonderful it is to live in a safe country. Instead, Monday night, they held their usual menacing and violence-tinged protest, which closed down a swath of Market Street and exposed Ess Eff once again as a consequence-free environment. According to the San Francisco Police Department, five protesters were booked on charges including felony aggravated assault, battery on a police officer and tampering with a vehicle. They went beyond their very American right to express their political views freely --?and illegally blocked off a portion of a main city street, keeping other people from going about their business.

Their purpose clearly was not to express ideas, but to interfere with the lives of other people, particularly people with real jobs and places to go. And for some -- those who showed up with masks because they planned on breaking the law -- the point was to disrupt and intimidate citizens.

What happens to protesters who assault cops? Russ Giuntini, chief assistant district attorney for San Francisco, told me, "When we first got here, the old philosophy was cops are supposed to take a punch." Now with a good case, he said, his office will prosecute. Police Officers Association President Gary Delagnes, however, wonders whether there will be consequences. "There are no repercussions in San Francisco," he told me.

Organizers said the Monday event was designed to honor Anderson's work fighting for human rights. "We're outraged to see what happened to Tristan as an American happens day in and day out to folks in Palestine," David Solnit, who is a friend of Anderson's, told KTVU.

So because Cricket's friends are outraged, they vandalize cars and block traffic. They have to know that their actions are not going to change the situation in the Mideast, but they can make you late for dinner. Also, they are affecting police overtime costs. Deputy Chief Kevin Cashman estimated that evening's action cost?$27,804.27 in regular-duty and overtime payroll costs. That's just one night in the big city. This is not police officers' idea of a good time. Cashman noted: "This is blood money. Officers often have to go into harm's way and are on the receiving end of objects being thrown at them."

Cashman was adamant in noting SFPD's duty to "to protect everyone's First Amendment rights." He noted that 90 to 95 percent of protesters simply are exercising their right to free speech. Often, many even tell police that they support law enforcement, not the violent anarchists.

The problem is, however, when an officer's skull is fractured -- as was the case with SFPD's Peter Shields during an anti-World Trade Organization protest in 2005 -- there are no angry marches closing down Market Street.