May 17, 2010 -- A hard-working supermarket clerk is bagging groceries at the end of the express checkout lane. He's doing a good job, but an impatient customer checks her watch and starts to criticize.
"Hurry up," the customer harps. "I don't have all day."
Rude customers are nothing new, especially in a grocery store located on a busy street in New York. What makes this scenario so objectionable is that the person bagging groceries has Down syndrome, and the customer starts to use indefensible language.
"Can you not understand me?" she yells, "You're absolutely retarded!"
Would you stand up and say something if you witnessed this cruelty?
To find out how customers would respond to such a scenario, we set up our "What Would You Do?" hidden cameras in a grocery store in Brooklyn, N.Y. While the scene described may seem extreme, it echoes behavior that happens all too often.
In this very store, a grocery clerk named Elvis -- who has an intellectual disability -- has been stocking shelves for more than a decade. His boss, Ivan, calls Elvis "the best," and holds him up as a standard for all other employees. Unfortunately, customers sometimes berate Elvis, using words like "stupid," "idiot" and -- the most hurtful -- "retard."
Madeline Will of the National Down Syndrome Society knows how this word damages people with special needs.
"It makes them feel less valuable, makes them feel less human," she said. "It's important to say, again and again, this is wrong, this is not fair, this is not how we treat other people."
But will customers take a stand when they see a person with special needs being verbally abused?
To find out we hired Josh Eber, an actor who has Down syndrome. Josh has spent his life acting opposite Muppets on "Sesame Street" and A-list actors in Hollywood movies, but for two days he played the part of a grocery clerk facing profound ignorance supplied by other actors, posing as customers in line.
WWYD?: Clerk With Disability
"You're absolutely retarded, dude! You have to go faster," our actress yelled as Josh bagged her groceries. Behind her, a woman's jaw dropped.
This customer, Kathleen, was clearly disturbed, but she stayed quiet until our actress engaged her.
"They shouldn't hire these people, right?" our actress asked.
"I don't know," Kathleen responded sheepishly. "I think they more, like, try to help them out."
"But it like they're oblivious to what's going on in real life," the actress pressed. "Like, their reactions are slow."
She was clearly horrified, but Kathleen gave in.
"Right," she said, "I know what you're saying."
Kathleen said later she thought the scene was horrible, but didn't want to risk a confrontation.
"She can lash out at me in any kind of way," she said, "and that's what I'm trying to avoid."
It's a common reaction. One woman said she didn't agree with the actress' language, but she politely laughed along as the actress made jokes about Josh.
"She was just blowing off steam," this customer reasoned.
After a number of quiet customers passed through the abusive scene, we wondered: Will anyone fight for Josh?
That's when Linda Tapia stepped in line.
"Oh no," our actress said as she put her groceries on the counter. "I didn't see this was the retarded line."
"Did you just say that?" Linda asked. "I can't believe you just said that!"
For a moment, it seemed that Linda was speechless, but then she summoned the words to put our actress in her place.
"If that was my child I'd deck you!" she shouted. "You're a crime! You're a crime."
When the scene was swarmed by "What Would You Do?" cameramen, no one was more proud of Linda than our actor, Josh.
"It's not right to treat people with Down syndrome like that," he told us. "No one puts us down. No one."
But will reactions be different if, instead of an adult, the ignorance comes from a clueless teenager? What if it comes from an intimidating man? And what will happen when the customer witnessing the abuse has a person with Down syndrome in his family?
Watch the full story on a special edition of "What Would You Do?" Wednesday at 10 p.m. ET.