The effects of deregulation

So, what are the arguments in favor of relying on companies to do what's right, again? Anbody? Maybe we really DO need governmental regulations to police companies whose only real concerns are their bottom lines and their investors? See also:
Enron and Arthur Andersen, WorldCom, Halliburton, Harken Energy, and on and on. This laissez-faire ideal of the "free market" is a joke. Business is just like the game Monopoly. Without rules, everyone would just steal money right out of the bank and put up hotels everywhere to try and screw everyone else.