This didn't happen recently. This was at my previous workplace. However I just learned about the outcome of it yesterday, after I had lunch with my former boss.
This story takes place 4 years ago. I worked for a company that is a large telecommunications company, and the majority of the leadership in my division (technical stuff, like networking, IT, etc) were all people who were promoted from within the company. It was rare for anyone to be in a leadership position from outside the company.
My boss was a really great guy, and always supported a healthy workplace, and upheld the standards of a proper work/life balance. Our HR team was also great in this regard.
His boss left the company at one point, and was replaced by someone who was hired from outside the company. He was a hard-nosed asshole that had lots of ideas about ways to change most aspects about how we worked, and didn't accept any of the feedback that was raised. Everyone hated him, and most of my colleagues were looking for new jobs, and making it very well known that they were doing so.
I won't go into tons of detail, because it's all very proprietary to that workplace and wouldn't make a ton of sense. But the important thing is that he had absolutely no experience in our industry, and his only past experience was being an upper management in the “Call centre” industry, which is not even slightly related to management of Networking/IT/Operations teams.
One day he scheduled every team that worked beneath him to attend small 4-person meetings (probably to prevent people from ganging up on him in the meetings), and he told us that he has caught wind of people talking about their salaries, and he gave us a 1 hour speech about how unprofessional he thinks it is, and he told us all extremely sternly that we would be terminated if he heard about any specific incidents of this happening again.
He was right that we were talking about our salaries. A few weeks prior to these meetings, my team had discovered that our salaries were extremely misaligned with eachothers, AND misaligned with the industry average. We were preparing to write a report and present it to HR.
Anyways, after I left my meeting with my boss's boss, I wrote a strongly worded email to HR. I told them that I had never been so insulted in my life, and I told them that I was disgusted and disturbed that our company was allowing this kind of person and their policies into the company, and I told them that I wanted them to know that his policies were not only against our company's own culture statement, but also very much illegal. I told them that I would be contacting the government labour board if I didn't receive an apology and hear him retract his statements.
After sending the email, I was almost certain that I was about to find myself in a somewhat difficult situation. I was certain that HR would have my back on this topic, but I was worried about the difficult amount of inquiries, investigation, etc. I also wasn't looking forward to the prospect of having a working relationship with this tyrant after having him reprimanded.
However, this turned out to not be the case. He left the company quietly the next week, and I never heard a single thing about my email.
Fast forward to yesterday, and I learned from my former boss that his boss was actually terminated based on my email. He also shared with me that after being terminated, he launched a lawsuit against the company for declining to pay him severance. Apparently, his contract had a clause that required a $300k severance payout in all scenarios of his forced departure, regardless of the reason for his termination. The company refused to pay him severance on some unknown grounds. Probably due to his actions being against labour laws, but neither of us know exactly why they were able to avoid paying him.
Know your rights. Even if you work for a great company, there's shitty and awful leaders everywhere, and they need to be kept in check.