"deadcode: I still can't believe that after they used the NYSE's data to prove that Goldman was gaming the system. Instead of sanctioning Goldman; they just stopped publishing the data that allowed it to be tracked."

How would less regulation and oversight prevent actions like this in the future?

That is one of my main issues with people that are so staunchly libertarian, the incentives they think that drive efficient free markets don't exist in the manner they think they do.

People are self interested and greedy for the most part, they rather have 1 dollar today than 2 dollars tomorrow.

Unfortunately I dont have enough information nor expertise in law to conclude whether this stuff should be illegal or not.

Currently it is not illegal; but let's pretend it was. Why would it require regulation to protect people from it. The court system would be sufficient; right? Maybe I'm misunderstanding your question.