From across the street, a man named Henry McNally marched toward the boys, yelling, "What the hell are you guys doing? LEAVE HIM ALONE!"
While McNally headed off to call the cops, as police recommended, another bystander, Cathy Owens, charged in.
"You're being little punks! That's a human being standing there! You don't get to lay your hands on him," Owens yelled. "Put that bat down right now!"
Keating said that the bat, instead of being a deterrent, actually propelled people to get involved.
"That bat signaled that it was in fact an emergency, and it made it crystal clear that action had to be taken," she said.
Owens also said, as a mother of teens, her intervention was instinctual.
"I wouldn't want my children to behave that way," she told us. "I wouldn't want them to have to see that in the town that they grew up in, either. It's horrible."
The simulated situation is not unrealistic. Experts are concerned because the so-called "bum bashers" keep getting younger. In 2007, three boys in Florida were charged with beating a homeless man using pieces of concrete. Two of the accused were just 10 years old.
Mary Brosnahan, the executive director of the New York City-based Coalition for the Homeless, said about 70 percent of those who attack the homeless are under the age of 25, and many are between the ages of 13 and 19.
"It's incomprehensible, and I think that it really starts with the parents' attitudes toward poor people," Brosnahan said. "For some people, they've stopped seeing them as people without homes. ... They're seeing them as subhuman."
Further fueling this "bum bashing" trend is the "Bumfights" video series, Brosnahan said. Widely popular among teenage boys, the DVD series casts violent pranks and physical assaults on homeless people in a humorous light.
"It's really shocking, because it's everything from getting people with alcohol problems drunk and having them fight each other to [an actor] actually stalking homeless people that are asleep and then assaulting them. ... And this is supposed to be funny," Brosnahan said.
For the people who stepped up to protect our homeless man, the situation was no laughing matter -- they were angry and quick to react. We wondered if the same reaction would occur if the teen harassed a homeless woman. Though our taunters' actions were less physical (no bat involved), the bystanders' responses were even faster and more physical.
One man, Mijo Suric, jumped in immediately when he saw the teens taunting the homeless woman. Suric yelled at the trio and shoved one of the teens who wouldn't step away from the woman.
"We do see women as more vulnerable, more helpless," Keating said. "That's the stereotype and that might have promoted even quicker action."
The woman victim not only elicited a quicker response but also an extra touch of compassion. After chasing the teens away, one person offered the homeless woman money. Others offered rides, and apologized to her for the teens' behavior.
For both the homeless man and woman, members of this community stepped in within seconds, but rarely did they work alone. Time and again, small crowds gathered to surround the aggressors.
"When we have a sense of community, we're empowered," Keating said. "And it was as if the people who intervened were saying, with their anger, 'Not here, not now, not in my town.'"
Brosnahan admits it's heartening to see so many identify with the plight of someone less fortunate.
"What I try to think of is, I didn't know this person growing up but can guarantee this isn't how they wanted to turn out," Brosnahan said. "They have the same dreams we do."
That's a sentiment echoed by Teresa Fuller, one of our victim's champions: "A lot of us are one paycheck away from being homeless ourselves."