The State Department has long advised Americans to avoid North Korea, but every year hundreds visit. Not all of those get to leave.

The announcement Sunday that a man identified as Kim Hak-song had been arrested brings the total to four American citizens now held in North Korea. At a time when tensions on the Korean Peninsula have been elevated by North Korea’s missile launches, a potential nuclear test and threats of armed conflict, the detentions add another complication.

So why do any Americans visit North Korea?

Most are tourists intrigued by a destination far different from the usual itineraries. They are willing to overlook warnings that have grown increasingly strident.

The State Department updated its travel advisory on Tuesday with a more forceful admonishment for American citizens to avoid North Korea, replacing the language “strongly urges” with “strongly warns.” The danger, the advisory continues, is “the serious risk of arrest and long-term detention under North Korea’s system of law enforcement.”