YNOT — Why anyone would be excited about baring all in freezing temperatures and two feet of snow is mind-boggling, yet for 10 years hundreds of people have run through a four-block stretch in downtown Boulder, Colo., wearing nothing but the shoes on their feet and jack-o-lanterns on their heads. Last year’s event attracted 150 male and female runners and scores of appreciative onlookers.This year, police warned potential participants in the 11th annual Naked Pumpkin Run they faced jail and listing in the sex-offender registry if they were caught. According to published reports, as many as 100 officers were stationed around Boulder Halloween night in case anyone missed the memo.

Apparently few did. Although police reported “a handful” of individuals took part, when corralled they were covered just enough to remain within the letter of the law. The question remains what the letter of applicable law says, exactly. According to the Wall Street Journal, it is not illegal to be naked in downtown Boulder. In fact, the city — home to a large University of Colorado campus and notoriously ultra-liberal — has a proud tradition of public nudity dating back at least to 1974, when thousands of UC students unsuccessfully attempted to ensconce Boulder in the Guinness Book of World Records as the site of the largest public gathering of naked people.

Nevertheless, “we’re a police department,” Boulder Police Chief Mark Beckner told the WSJ. “We enforce the law.”

In this case, the law Beckner was determined to enforce turned out to be a state statute that classifies as a Class 1 misdemeanor any exposure of genitals “likely to cause affront or alarm.”

According to the WSJ, “A throng of naked people with jack-o-lanterns on their heads is, by definition, an alarming sight, Chief Beckner says. Therefore, it’s illegal.”

On its website, the group that organizes the nude runs in Boulder, Seattle and Portland, among other cities, advised potential participants in this year’s events, “the violation of the Western societal more, enforced by law, of unclothed public exposure can indeed land you legal consequences. Furthermore, the decision to participate is yours and yours alone.”

Beckner said putting a stop to the run had less to do with public morals than rowdy behavior. In recent years the event has become “a free-for-all,” he told the WSJ, so he felt obligated to put an end to the nonsense for safety’s sake. His department issued 12 indecent-exposure citations during last year’s event, although “The Pumpkin 12,” as they became known, either saw the charges dropped or reduced to disorderly conduct. The most onerous penalty constituted a few hours of community service.

A Boulder attorney called Beckner’s line in the sand “pre-emptive outlawing of a gathering.” All 10 candidates for Tuesday’s city council election said they disapproved of Beckner’s heavy handed crackdown on a little harmless fun. Even the Boulder County district attorney told the WSJ he thought the chief might be going a bit too far.

The American Civil Liberties Union went further in its condemnation of Beckner’s decision to deploy not only patrol officers but also SWAT teams to prevent naked hijinks from erupting in 2009. The local chapter of the ACLU called the crackdown a clear-cut violation of participants’ civil rights.

The late-night rite “seems somewhat quixotic, but our Bill of Rights does not judge the content of free expression,” ACLU Boulder County Chapter Chairman Judd Golden told the WSJ.

Only one arrest was made Halloween night, a police spokesman told local newspaper the Daily Camera, and it wasn’t related to the pumpkin run.