Employers have the right to require employees to wear uniforms, but they don't have the right to completely control everything on the uniform, the 5th Circuit Court of Appeals told In-N-Out.

Employees at an Austin, Texas, location wore "Fight for $15" campaign buttons, and management told them to remove them, citing In-N-Out's dress code, which required nine different parts: "white pants, a white shirt, white socks, black shoes, a black belt, a red apron, a gold apron pin, a company-issued name tag, and a hat," according to the Society for Human Resources. 

Their handbook also stated that  "Wearing any type of pin or stickers is not permitted."

This seems clear and legal, as companies can require dress codes. But, In-N-Out requires employees to wear buttons twice a year: for Christmas and to raise money for charity. The National Labor Relations Board said that indicated that there were no safety reasons for the ban, and that the dress code wasn't enforced as strictly as it was written.

But, this doesn't mean your employees can have a free-for-all on what they wear. The employees wished to wear a very specific pin: one that falls under a "protected concerted activity." 

This means, essentially, that employees were using their protected right to advocate for a raise. Employers are strictly forbidden from preventing employees from discussing employment conditions, including salaries.

If In-N-Out hadn't allowed exceptions to their rules about buttons, it's likely that they would have been successful in prohibiting the "Fight for $15" buttons. 

Can you require strict uniforms?

This ruling doesn't prevent you from prohibiting changes to your uniforms. You can require that employees follow it strictly, but if you do that, do not allow exceptions. Once you allow the exception, you open yourself up to a case, if the employees engage in a protected activity. It's unlikely that the court would have required In-N-Out to let employees wear "Save the Whales" buttons, as they aren't related to their working conditions.

Can you do anything to prevent such discussion at work?

Obviously, In-N-Out doesn't want customers thinking their employees are underpaid, and neither do you. Can you do something to prevent such workplace discussion?

The answer is, treat your employees correctly and you don't need to worry. The fact that employees are paid less than $15 an hour does not indicate that these employees aren't earning market rates.

When you try to prevent your employees from talking about their working conditions, what you're telling them is that you know their situation is bad, so shhhhh. 

While I think the NLRB and the 5th Circuit were a bit extreme here in allowing the buttons, it's a reminder to you that the NLRB takes concerted activity very seriously, and you should too.