North Koreans walk, some pushing their bicycles, along a street in Pyongyang in this file photo from October 2015 (AP Photo/Wong Maye-E)

Young Pioneer Tours bills itself as a specialist serving adventurers with a desire to see North Korea and other destinations “your mother would rather you stayed away from.”

Based in China, this agency organized the tour during which a University of Virginia student was arrested Jan. 2 at a North Korean airport. Otto Warmbier, 21, of Cincinnati, was accused of a “hostile act,” but there was little other information available about what led to his detention.

[North Korea: Virginia student arrested for ‘hostile acts’ while on tour]

One of the world’s most isolated countries, led by a Communist dictatorship, North Korea is nonetheless a magnet for a certain kind of traveler who wants to see a corner of the world that is way, way off the usual tourist track. And some of them are students.

Exactly how many Western students visit every year is unclear, but one knowledgeable source — who declined to be identified because of the sensitivity of Warmbier’s situation — estimated Friday the total is in the hundreds.

The U.S. State Department “strongly recommends against all travel by U.S. citizens” to North Korea, citing the risk of arrest and long-term detention due to the country’s “inconsistent application of its criminal laws.”

Young Pioneer Tours declined to answer questions about its activities in North Korea and why it advises travelers that its tours are safe despite the U.S. government warning.

“Our primary concern is the safety of our customer,” Gareth Johnson, founder of the tour company, wrote in an email. “It is with this in mind that the information we have already shared is all we currently intend to share.”

Experts in travel to North Korea say that it is essential for any visitor to follow laws, rules and customs. Don’t distribute religious materials. Don’t wander off the itinerary of an official tour group. Observe restrictions on photography. Be careful in references to the government and especially the ruling dynasty.

In recent years, more Western students have come to China to study abroad. For many of them, Pyongyang is a draw for those wanting to take a quick side trip from Beijing. Young Pioneer Tours says it can help travelers compete in a Pyongyang marathon, observe the Demilitarized Zone on the South Korean border or ski at the Masikryong Ski resort.

“I’m passionate about travel to so called ‘rogue nations’ and changing people’s often incorrect perceptions of them,” wrote one of the company’s guides, Shane Horan of Ireland, on its website.

The tourist industry has grown in recent years, spurred in part by North Korea’s desire for foreign cash. Critics say foreign tourism props up a dangerous and repressive regime.

[From 2014 archive: North Korea tries to lure tourists to earn foreign currency, but 2 on trial]

In 2012, 15 students from Columbia University’s School of International and Public Affairs visited North Korea on a seven-day research trip. The group obtained a formal invitation from North Korea through a professor’s contacts with the United Nations.  “The chance for SIPA students to visit, observe and study North Korea was too good to pass up,” the school’s interim dean at the time, Robert Lieberman, said in a news release.

On Friday, some travelers contacted through Facebook said their trips to North Korea had been worthwhile.

“The thing is, if you are respectful of their culture, and don’t go there looking to do something that is against their laws, you will have no problem traveling to the DPRK [Democratic People’s Republic of Korea],” wrote David Hart, who lives and teaches in South Korea. He said he visited the North at about the same time Warmbier was there. “I am a U.S. citizen with a U.S. passport. I took in my laptop and my cellphone.”

Hart recalled a revealing excursion into a “regular” grocery store. “We were allowed to exchange our money into North Korean won and spend an hour buying whatever we wanted to buy. And the shelves were stocked full of food and goods. All kinds of foreign beer, including Guinness, Soju (rice wine drink of Korea), other liquors, cigarettes, candy, Nutella, chips, soft drinks, meat, fish — and the place was packed. …. One cute little girl kept pointing and smiling at me throughout the store, and her parents beamed. It was really a very authentic experience, and meant a great deal to me.”

Chris Buchman, of Little Rock, Ark., said he had visited briefly as a tourist. “In addition to western students and tourists, there are a lot of Chinese and other Asian tourists going to North Korea these days,” he wrote. “Most people seem to report having had positive experiences, albeit with a lesser degree of freedom of movement that one would expect in most countries.”

As for colleges, they are of two minds about student travel. They want students to explore as much of the world as possible. And they want them to stay safe. Sometimes there is tension between those two goals.

Goucher College, a liberal arts school in Baltimore County, Md., requires students to study abroad. Jose A. Bowen, president of the college, said the school would discourage students from visiting North Korea. But he understands why a student might want to go there.

“There’s a fundamental tension,” he said. “You want students to be safe, but you also want them to be learning.” Sometimes you learn more by being in a place with problems, he said. “The whole mission of the institution is to make people a little uncomfortable so they rethink their assumptions.”

Bowen noted that even when students visit a supposedly safe destination they can face jeopardy. Four of Goucher’s students were in Paris at the time of the terrorist attacks in November. “Within hours we were able to get in touch with them, verify their safety and call their parents,” he said.

This item has been updated.