Pro-democracy activists yell and hold signs in opposition to a speech being given on the main stage during a rally on the streets outside Hong Kong's Central Government Complex on Nov. 21, 2014 in Hong Kong. (Chris Mcgrath/Getty Images)

The young design student nervously picked at her noodles as she recounted being pulled aside last week at the Chinese-Hong Kong border.

It was supposed to be a routine trip for inexpensive design materials from China. Instead, she spent more than an hour being searched and interrogated by border guards, and was ultimately put on a bus back to Hong Kong. She was told she was a threat to national security.

The reason: She had been videotaped at a protest months ago in Hong Kong.

“At first I just couldn’t believe it. Look at me,” said the petite 23-year-old who stands barely over 5 feet. “How could I threaten anyone’s security?”

A growing number of people in Hong Kong who have taken part in the city’s pro-democracy demonstrations are suddenly finding themselves denied entry to China. The action has shocked many and sparked the widespread belief that Chinese authorities have assembled a blacklist in recent months with hundreds, perhaps thousands, of names.

Hong Kong protesters remained defiant as police and bailiffs cleared barricades and tents from part of an occupied site. (Reuters)

In a well-publicized incident last week, three leaders of the ongoing student protest were stopped while trying to fly to Beijing to confront Chinese leaders. Their attempted trip — staged in part as a form of protest — drew international headlines, but subsequent cases have been more surprising because they involve relative unknowns — not leaders — who merely participated in the protests, which included hundreds of thousands of others.

For some, the denials threaten their livelihoods because of how intertwined Hong Kong’s economy is with mainland China’s. They may also cast a chilling pall on freedom of expression here and have already fueled anxiety among protesters, fearful of the possible consequences of being on China’s watch lists.

The 23-year-old design student who was stopped last week, for example, asked to speak anonymously for fear of further retaliation by Chinese authorities.

Since her hassle at the border, she has avoided saying anything personal or sensitive over the phone in case it is being tapped. Before speaking with a foreign reporter, she checked his press card and compared his face with online pictures searched for on a smartphone.

“Everything we watch on the news about mainland China — the paranoia, human rights abuses, the way the Communist Party treats its citizens — for the first time in my life, I feel that way about Hong Kong,” she said.

When this former British colony was returned to China in 1997, Beijing promised that its residents would continue to enjoy freedoms unseen on the mainland. People here hold large annual rallies on the anniversary of the Tiananmen Square crackdown and freely discuss China’s political system on social media outlets such as Facebook and Twitter that are banned on the mainland.

Another promise was suffrage, and at the heart of the current protest movement — called the Umbrella Revolution or Occupy Central — is the demand that Hong Kong residents be allowed to choose the city’s leaders themselves, instead of having candidates vetted ahead of time by Beijing.

As public support for pro-democracy protests in Hong Kong dwindles, some say it might be time to end the action that is blocking large parts of the city. The protests started almost two months ago. (Reuters)

“This new trend of denying entry is a powerful weapon, not just against students but against professionals who want to support the movement,” said Willy Lam, a political analyst at the Chinese University of Hong Kong. “Everyone these days needs access to China. It doesn’t matter if you’re an accountant, architect or anything else, that’s where the market is.”

According to the Chinese government, Hong Kong residents made 154 million trips to the mainland in 2013, up 3.4 percent from the year before.

Among those who have reported being turned away at the border are a member of the student union at Hong Kong Baptist University, a Lingnan University student who was trying to buy books in the southern Chinese city of Shenzhen, and a City University student trying to visit relatives.

Eric Tang, 21, a student at the Open University of Hong Kong, said he was turned away Nov. 9 while trying to go to Shenzhen with his girlfriend to shop.

Over two hours, he said, guards took his Hong Kong ID cards and searched his body and bag. Then they turned on his laptop and rifled through that.

He said he was surprised because he is not a famous figure like the Hong Kong democracy activists and legislators who have been denied entry in the past. He is a Democratic Party member, which may have gotten him tagged, but he said he suspects his denial was triggered by a July 1 protest he attended — a summer precursor to the occupying movement that continues to paralyze parts of downtown Hong Kong.

Many recently denied entry attended that summer protest, which drew one of the biggest pro-democracy crowds in recent years. More than 500 people were arrested and released with warnings.

Tang said he had no problems traveling to China throughout October to visit his sick grandfather. But now, his relatives, already nervous about his democracy advocacy, are worried that his troubles will affect their freedom to travel to China. Tang said he worries, too, whether his trouble could have an impact on friends and classmates.

For the design student, who was also arrested at the July 1 protest and released July 2, not having access to China may mean buying costlier, inferior design materials in Hong Kong, and perhaps a lower grade in her classes.

She remains deeply rattled by the border guards’ interrogation. But if she had it to do all over again, she would still attend the protests, she said. “I have nothing to be ashamed of. I have no regrets about what I did.”