This is the premise of a deeply affecting and effective social experiment and accompanying three-minute video created by the Miami office of David, the agency partner for Burger King. The spot is called “Bullying Jr.,” and was created in honor of National Bullying Prevention Month.

Some 30% of kids around the world report being bullied at some point. To see what would happen if it happened in public, the David team hired teen actors to harass another kid in a real Los Angeles-area BK restaurant. The premise was simple: Would customers be more likely to stand up for a bullied junior human or a bullied junior Whopper?

At the risk of spilling any spoilers, watch it now.

David, like most ad agencies, likes to proclaim its creative bona fides, and in this case, it seems particularly well deserved.

Other recent risky ideas include this Cannes Grand Prix winning print ad campaign, which featured photos of real Burger King restaurants engulfed in smoke and flames, and pointed out that more BK restaurants have burned down than any other fast-food chain. “Flamed grilled since 1954,” the ads said, clearly playing with fire.

They also threw Google Home under the bus in another hilarious online spot, which earned them the Direct Grand Prix at Cannes, 9.3 billion global impressions and $135 million in earned media.

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But the team clearly knows how to pull heartstrings. Last year, the creative team broke new ground by letting Burger King’s always silent King character finally speak – but in sign language, to celebrate National American Sign Language Day. Turns out, there was no sign for a Whopper, but thanks to a crowd-sourced campaign, there is now. The call to action video, which also includes an ASL proficient King asking a diverse array of deaf customers for input, is equal parts delightful and moving. (It’s also silent.) The first ASL sign co-created with a brand got more than 200 million media impressions.

The agency seems to have diversity built into its DNA — an unscientific scan of their website shows that nearly one-third of their employees are women and about the same percentage appear to be people of color. David was founded in Brazil by three Ogilvy veterans, Anselmo Ramos, Gaston Bigiom and Fernando Musa, in 2011. (Hence the name David, a nod to David Ogilvy.) Their Miami office opened in 2014.

The agency’s commitment to inclusion, playfulness and radical conversation came in handy for the bullying experiment. The vast majority of the customers – some 92% – opted not to intervene as the teen boy was bullied near them, but did complain when their burger was beaten up before it was served.

It didn’t take long for online commenters to notice that the people who stood up for the bullied kid appeared to have some familiarity with the experience. Both of the extraordinary people who stood up for the teen showed restraint, compassion, and patience, even for the bullies.

This is all a strange lesson to learn from a burger joint, to be sure. But it really works. To that end, I tip my hat to the people who failed to respond to the kid in need but still gave their permission for their images to be used. It may not have been a good look on them, but it was an excellent reminder that knowing what to say — and when to say it — is harder than it seems.