Just like every ponzi scheme, the trick is to get out in time. I wonder how many people worked for Madoff but left before it all fell apart. How many of them are now working in other financial jobs? or Lehman bros.
Fun fact, one of the biggest benificiaries of madoff's scheme is believed to be madoff's victim/investor Jeffry Picower.
Picower may have figured out it was a Ponzi and agreed to "invest" in the scheme when Madoff became desperate for liquidity. But there was plausible deniability as he was just a guy who bought in at times and sold off at others.
So maybe the actual trick is people like Picower, who identify these schemes and then leverage the scheme to their advantage while all along looking like another victim and never once speaking about their suspicions or getting involved in the mechanics. Which brings me to think perhaps the Picowers in SBF's scheme were some of his investors who figured out it was a scheme but believed they could cash out before it toppled.
Scheme no, but it was a company that fell apart quickly. Employees would be better served to get out and secure a new job the day before a crash rather than the day after.