As I also pointed out, this does not mean that one cannot commit fraud vs a short-seller. However, from what I gather, the rights of short-sellers under 10b-5, based on a "fraud on the market" theory, are rather murky in established caselaw and differ between federal circuits.
Nopes, SEC makes sure that laws and regulations are followed. Investigations in Enron also led to people losing money.
In the realm of securities fraud, I would say that the private securities bar does about 90% of the impact (in terms of judgments and settlements). And successful criminal referrals a la Enron are quite rare, proportional to the actual amount of fraud going on.
By the way, Enron was a fraud against its own investors. Enron was not about fraud against short-sellers, it was fraud against purchasers of Enron stock. Not that short-sellers don't deserve honesty, just saying that they do not typically receive much love from regulators. From what I can tell, it seems this is not solely due to the disposition of said regulators, but also because of legal uncertainty around short-sellers' rights under securities laws.