Preventing future 'Enron's'
The best way to prevent future 'Enron's', IMO, is to make an example of those involved. Strip them of all their assets and throw them in jail for a long time. That will make others think twice.
Enron hurt many more people then those who lost their Enron 401K and Enron jobs. It hurt the American economy. Here in Houston, it flooded the job market with thousands of people and hurt unemployment. It was like the first domino that caused many more to fall.
Throw the book at them. Take their money away. Make them an example.