My friend works at a San Diego branch of one of America’s largest corporations. The company’s annual revenues are in the billions of dollars.

In 2010, Fortune listed my friend’s employer as “one of the world’s most admired companies.” In 2011, the company stole from my friend and thousands of other employees — but not the employees protected by unions.

My friend’s story highlights the importance of collective bargaining and shows how employers take advantage of workers who can’t join together to negotiate. Here’s the gist of how it went down.

Two months ago, my friend’s boss announced that the company was adjusting its two-week pay periods. Instead of starting each period on a Friday, the company would start them on Saturday.

“Your next paycheck is going to be smaller than usual, because it will only cover 13 days instead of 14,” the boss said. “But the paycheck after that will cover 14 days again. Any questions?”

“I’ve got a question,” my friend said. “Doesn’t that mean we’re missing out on a day of pay?”

“No,” the boss responded. “That day was just shifted into the following pay period.”

“So doesn’t that mean the next pay period should cover 15 days?” another co-worker asked.

“No,” the boss replied. “Basically, the extra day will show up on the last paycheck you receive from the company.”

“You mean when we quit or retire?” my friend asked.

“Yes,” the boss said.

“That’s ridiculous,” one co-worker blurted.

“If I’m missing a day of pay, I want an extra day off,” another said.

“I’m sorry,” said the boss. “There’s nothing I can do.”

My friend felt not just frustrated but violated, like he had been burglarized. Then he remembered something: Some of the company’s offices in other cities are unionized.

My friend contacted one of them and asked if they were facing the same issue.

“No, we got that missing day paid up front,” was the response. “Our union would never let the company screw us like that.”

Any questions?