About 50 kilometers from central Seoul, Incheon Airport is one of the busiest air gateways anywhere in the world. While most people go to travel abroad, some have a different purpose: to see their favorite idols up close.

Celebrities in Korea, especially K-pop idols, often arrive fully styled from head to toe, emerging from a van when embarking on a tour or doing promotions in another country. And as soon as they get out, the airport shoot begins as photographers hurriedly take out the cameras.

Sometimes entertainment media outlets are tipped off in advance by agencies in the hopes of generating coverage for lesser-known celebrities.

The practice has become an industry norm over the years, as more K-pop idols now boast bigger global followings and tours around the world. It has also coined the term “airport fashion,” as idols’ off-the-stage looks provide style inspiration for many, creating exposure for fashion brands.

Fans too seize on this opportunity to take pictures and give gifts or impart greetings, if they are lucky, to the stars.

As of late, however, the industry practice that makes an airport sound like an innocuous playground has been marred by worrying signs.

Problems begin to arise when obsessive fans, known as “sasaeng,” follow idols past the immigration barrier and into the departure lounge, where many artists or agencies draw a line.

One fan, who wished to stay anonymous, said she was once told by her favorite member of an idol group that while coming to the airport was OK, the singer wanted to be left alone once past immigration.

She explained that idols find themselves in a corner after the immigration check-in, because there is no way out until the plane lands at their destination.

“After immigration at an airport, there is no escape. There is nowhere else to go. You have them cornered and you are like a cat and they are a mouse in a corner,” the fan said.

Knowing their idols are trapped, others are ready to exploit their vulnerability, selling flight information to those wanting to get as close as possible to the stars.

Many of these exchanges take place via Twitter, where searching the right few hashtags leads to accounts that appear to openly sell personal information.

And sometimes, it’s not just K-pop stars whose flying experience is ruined, but other passengers unfortunate enough to be on the same flight as well.

In 2018, Korean Air had to disembark just before takeoff when fans of Wanna One got on board the plane to see the group, only to suddenly then demand a refund and ask to leave the plane, forcing everyone else to get off.

An official at Korean Air said this was in part why the company began enforcing an additional fee of 200,000 won ($172) last year on those who decide not to board an international flight at the last minute after passing immigration.

By Yim Hyun-su (hyunsu@heraldcorp.com)