1. How is this detected by the SEC?
2. Why isn't this something that is easily detectable by the average investor?
That was from a quick Google search, so I'm sure there are many more accusations. It seems like the SEC has never been the 'first' to detect a fraud, and they've frequently ignored ones that have been pointed out to them (such as Madoff).
Because much crypto trading is just transactions within some crypto exchange, and never makes it to the blockchain.
"Get your pristine 1950 silver eagle collection for 5000$ before they're all sold out!"