system
Given the following post, respond as if you're commenting on Reddit:
human
Filing a complaint against PI for mistreatments of employees

In past I worked for a bad PI. I left the lab without asking for her recommendation. A year later, I am witnessing another employee (a technician) of hers leave the lab after working for 2 years. He asked for her recommendation and she is saying negative things about his work ethics. She is lying. She has lied on multiple occasions in past, for petty things to very serious matters. Should he complain to HR about her in his exit interview? Or is it not worth it? Do they every take any action against PIs? I left without complaining but I want to do so now, so future employees don’t suffer. It’s been an year since I left. Should I file a complaint?
gpt
Speaking as a senior administrator, yes, you should complain.  You will get zero satisfaction in the sense that you will never see the impact of your complaints, but good institutions have memory and when the opportunity comes, repeat offenders will be kept from positions of authority and/or pushed out altogether.