It’s in the article. They were fined for it. Sounds like there are a number of ways to hide from FTD
“The SEC found that Goldman Sachs was mismarking logs and allowed customers to engage in short selling without determining whether the securities could reasonably be borrowed at settlement. - In 2013, a Charles Schwab subsidiary was found liable by the SEC for a naked short-selling scheme and fined $8.2 million. - The SEC charged two Merrill Lynch entities in 2015 with using “inaccurate data in the course of executing short sale orders”, fining them $11 million”.