MA XUEJING/CHINA DAILY

Twenty-one "brokers, recruiters and employers" in the United States that allegedly used illegal means to help more than 1,000 foreign youths get student visas (in some cases employment visas) were arrested in a sting operation by the US Department of Homeland Security earlier this month. The students, mainly from China and India, can now have their visas cancelled and be deported.

To sniff out the fraudulent agencies, US federal agents set up a fake university three years ago－the "University of Northern New Jersey"－which was not staffed with instructors or educators, had no curriculum, and held no actual classes or other academic activities.

Indeed, sting operations like this have helped solve some tricky cases, which normally involve corruption, sex trade, drug smuggling and gun regulations, even terrorism.

Over a year ago US law enforcement officers used a similar tactic to arrest a 20-year-old man after he purchased two guns and 600 rounds of ammunition in Ohio. His Twitter posts sympathizing with Islamic terrorists led to an undercover FBI operation, which eventually prevented an attempted attack on the US Capitol.

A sovereign state does have territorial jurisdiction over the affairs within its borders according to international law, which is why citizens are told to abide by local laws when traveling abroad.

Although legal and effective, the US' sting operation against fraudulent agencies is not without flaws, because many of the foreign students will suffer just because they didn't know much about the country or the scam.

The paradox is that a sting operation, which is conducted to lure criminals or potential criminals planning to commit a crime and arrest them, could also be applied to people who have no intention to break the law. If law enforcers out to frame "criminals" illegally exploit such people they could be guilty of intentional instigation.

According to the US Supreme Court, defendants who have no criminal intentions before being enticed to commit a crime are considered "unwary", meaning that the enforcement of law against them may be illegal. However, they stand little chance of defending themselves against the law enforcers' possible framing if their personal characters and criminal records show they are related to the alleged crimes.

Undercover agents in a sting operation, on the one hand, are under constant threat while conducting investigations, ranging from drug crime and sexual assault on women to illicit cabs. On the other hand, there could be a wave of public complaints, even lawsuits demanding huge compensations from the country, if they bugle their job. That explains why most countries act prudently in authorizing such operations to identify crimes and criminals.

The fraudulent agencies in the US should definitely be held accountable based on their violations of the US and Chinese law, because they have cheated a number of foreign students who dreamt of entering a real US university. But the students' illegal stay or overstay in the US might deal a heavy blow to China's international image as well as that of Chinese students overseas.

The author is an associate professor of law at Southwest University of Political Science and Law.