The Boy Scouts’ motto is: Be prepared. Who knew it meant preparing to defend themselves against purple-shirted union thuggery over community service? Kids, pay attention. This is a teachable moment for all of you on power, politics and Big Labor’s culture of corruption.

Last week at a city council meeting in Allentown, Pa., a top official of the local Service Employees International Union chapter ranted about 17-year-old Scout Kevin Anderson’s park cleanup work. Anderson devoted some 200 hours to the job in order to earn an Eagle Scout badge. He picked up trash and helped clear a 1,000-foot walking path with fellow members of Boy Scouts Troop 301 of Center Valley.

But SEIU’s Nick Balzano gave them hell instead of thanks.

Balzano disparaged altruistic efforts in city parks and asserted that “there is (sic) to be no volunteers” since his union members were laid off. He then issued a witch hunt threat: “We’ll also be looking into the Cub Scout or Boy Scout who did the trails. We may file another grievance on that.” Citing union rules, he gave the Allentown city council, the Boy Scouts and all potential volunteers an iron-fisted ultimatum: “None of them can pick up a hoe. They can’t pick up a shovel. They can’t plant a flower. They can’t clear a bicycle path. They can’t do anything. Our people do that.”

That’s right. Balzano was ready to bludgeon the Boy Scout because his gung-ho volunteerism posed a threat to the SEIU labor monopoly. The outrageous display of Boss Balzano’s union protectionism provoked a national furor. SEIU headquarters in Washington immediately blamed “the disreputable Fox News and other right-wing outlets like Michelle Malkin’s accuracy challenged blog” for the backlash. While decrying their critics’ “fiction,” SEIU distanced itself from Balzano, denying that he was a top union leader and dismissing his remarks as “unauthorized.”

Fact: U.S. Department of Labor records from 2008 (their most recent filing) show that Balzano is no rogue rank-and-file member. He currently serves on the SEIU local’s executive board and previously served as president.

Fact: The union tried to minimize Balzano’s grievance threat as “inappropriate.” But the dirty open secret is that public-sector unions have routinely attacked volunteer workers who threaten their stranglehold.

Last June, union officials in Baraboo, Wis., filed a complaint against volunteer firefighters who built sandbag barricades to protect the city from record flooding. They whined that city Department of Public Works employees should have been called first and demanded overtime pay (for work they didn’t do) to compensate them.

Yes, kids, the city was knee-deep in water and the government union got mad that other people scrambled to work together in an emergency to put sand in bags, save homes and help their neighbors. Public-sector unions aren’t about serving the public interest. They’re about serving their people, their power and their self-preservation.

In Montpelier, Vt., several years ago, the teachers union went after a superstar educator, Bill Corrow. The students, staff and supervisors at his school loved the social studies teacher and Vietnam veteran. But the Vermont Education Association hated him because he was a volunteer who did not accept payment for his elective course. Teachers unions are all for parents and schoolchildren volunteering their time to engage in political lobbying and power-expanding initiatives on the union’s behalf. But God help the community service-oriented individual with a passion for sharing his knowledge in their classrooms.

In California, union heavies in the Sacramento area sued a nonprofit environmental group for using college-age volunteers on a state-funded project to clean up a canyon and build a community trail. Big Labor dusted off an old law that requires community service volunteers to be paid prevailing wages for doing the same kind of cleanup that Allentown Boy Scout Kevin Anderson was punished for doing freely. The law was finally repealed, but not without a brass-knuckles fight.