What is the role of commerce to government when it comes to
fraud?
A good example is godaddy.com and Yahoo.com. This is how the fraud works. You search for
a domain name on Yahoo.com. You find
that it is available but you don’t take it immediately. If the name sounds like it could be a
business (as opposed to a personal name) you will find a week later that the
domain you were searching for is for sale at godaddy.com. Not only has godaddy.com stolen the name you
were interested in, but godaddy.com runs an auction site to auction off the
name you were interested in, if you won’t buy it directly from them.
Godaddy.com and Yahoo.com are running a fraud. 
Should the government protect consumers from fraud? Of course! Commerce is not a moral system, never was never will be. It is up to the society in which commerce operates to apply its moral system to commerce. Our society has, over roughly 150 years of experimentation, concluded that caveat emptor (buyer beware) doesn’t work. Consumers spend more when they know that they are safe from fraud. So the government, in order to promote commerce in our particular moral environment, defines and punishes fraud.
By prosecuting fraud, the government also reduces murder and violence. If I bothered to find godaddy.com or I happen to drive past Yahoo.com headquarters, I would see that both companies pay the price for trying to cheat me.