The problem is exacerbated when one considers how much of online activities are potentially criminal. For example, the FBI could set up Web sites offering to sell or give away software or services to "crack" CDs, game systems, DVDs or BluRay disks, to unlock iPhones, or to otherwise supply technologies that might be helpful in circumventing a "technological protection designed to protect a copyrighted work" under the Digital Millennium Copyright Act (DMCA). The law's trafficking provisions makes it illegal to:

. . . traffic in any technology, product, service, device, component, or part thereof, that is primarily designed or produced for the purpose of circumventing protection ...

Clicking a link makes you liable for attempted trafficking.

Indeed, there are literally thousands of things that are illegal to possess -- from certain kinds of information, such as classified data, credit information and bank secrets to burglar’s tools and certain kinds of cheese. Law enforcement would not have to wait for the unwary to actually obtain any of this contraband. Instead, they would merely have to lure potential buyers to click on a link that purports to lead to the contraband.

Mouse trapped

There is also the genuine issue of entrapment.

Any future use of a click-crime technique must ensure that it has taken steps to make sure that the suspects they are catching are people who intended to commit a crime and not simply those ensnared by the trap.

In 1984, a 56 year-old veteran from Nebraska named Keith Jacobson ordered some magazines from an adult bookstore in California. Jacobson believed he was ordering adult pornography, but instead was -- in his words -- "shocked" to find magazines with naked images of minors. Under the law at the time, purchasing the magazines was perfectly legal.

Yet, when the bookstore’s offices were later raided by the FBI and Jacobson’s name was found on the mailing list, the U.S. Postal service then began sending Jacobson surveys about his sexual predilections from fictitious companies they created, such as "Midlands Data Research" and "Heartland Institute for a New Tomorrow." The government, through an undercover agent, began to engage in a dialogue with Jacobson about his sexual preferences. Nearly three years after Jacobson had allegedly ordered the magazines, the U.S. Customs Service set its eyes on Jacobson, creating a fictitious Canadian company and mailing Jacobson a brochure advertising the sale of photographs of young boys engaging in sex. At the same time, the U.S. Postal Service created a company called the "Far Eastern Trading Company" also encouraging Jacobson to buy child pornography. His curiosity "piqued," Jacobson responded and ordered a magazine from the Far Eastern Trading Company and was promptly arrested.

The United States Supreme Court struck down his conviction noting:

In their zeal to enforce the law, however, Government agents may not originate a criminal design, implant in an innocent person's mind the disposition to commit a criminal act, and then induce commission of the crime so that the Government may prosecute. Where the Government has induced an individual to break the law and the defense of entrapment is at issue, as it was in this case, the prosecution must prove beyond reasonable doubt that the defendant was disposed to commit the criminal act prior to first being approached by Government agents. 

…[A]n agent deployed to stop the traffic in illegal drugs may offer the opportunity to buy or sell drugs and, if the offer is accepted, make an arrest on the spot or later. In such a typical case, or in a more elaborate "sting" operation involving government-sponsored fencing where the defendant is simply provided with the opportunity to commit a crime, the entrapment defense is of little use, because the ready commission of the criminal act amply demonstrates the defendant's predisposition. Had the agents in this case simply offered petitioner the opportunity to order child pornography through the mails, and petitioner - who must be presumed to know the law - had promptly availed himself of this criminal opportunity, it is unlikely that his entrapment defense would have warranted a jury instruction. But that is not what happened here.

By the time petitioner finally placed his order, he had already been the target of 26 months of repeated mailings and communications from Government agents and fictitious organizations. Therefore, although he had become predisposed to break the law by May, 1987, it is our view that the Government did not prove that this predisposition was independent, and not the product of the attention that the Government had directed at petitioner since January, 1985.

In essence, under the law of entrapment in the United States, if the government merely provides an opportunity for an otherwise predisposed individual to commit a crime, the sting operation passes muster, but if they essentially plant the idea of criminal conduct in a person who is otherwise not predisposed to commit a crime, it may constitute entrapment.