For many parents, having a front-row seat at move-in provided an opportunity to set a few rules.

Ms. Ding, the farmer, said she worried about how her son, Mr. Yang, would fare in a city with so many skyscrapers and distractions. He came down with fevers frequently as a child. And he sometimes seemed addicted to his cellphone, she said, playing games and devouring sci-fi novels.

After the more than 36-hour journey by train and bus from their hometown in Hubei Province to the tents in Tianjin, Ms. Ding offered some advice. No video games. No lazy friends. And no romantic relationships.

Mr. Yang, with thick black frames, a bright yellow T-shirt that said “RESURRECTION” and a faint mustache, looked skeptical. “That’s not necessary,” he said.

They agreed to disagree, and promised to stay in touch regularly by phone and by WeChat, a popular messaging app. So long as it did not interfere with his studies.