I worked at a health care tech company in Silicon Valley that actively defrauded medicare. When the medicare inspectors came the owner's daughters had a bunch of their friends from college (who didn't work there) sit at computers and pretend to be working, then they told the inspectors all these random people were registered nurses and full-time employees who were helping patients (and thus being billed for). It was a total sham.

I reported it and quit but they managed to stay in business and keep getting government contracts.

One of the disgruntled doctors from that company made a whole website about some of their fraud: https://hiller.whitecollarcrooks.com/

They also bragged to us about how one of their daughters was dating a Glassdoor exec and had him take down all their bad reviews.