Also, getting away with an event like that hurts confidence in the stock market as a whole. It's not not purely about immediate damages to people in the market

Also, getting away with an event like that hurts confidence in the stock market as a whole. It's not not purely about immediate damages to people in the market, it's also about how willing people are to participate in the future. A fraction of a percent of less people participating or slowing activity likely amount to many multiples of the damages from this event. The SEC would be extremely motivated to find these people to make an example of them so others think twice in the future.