It's not that hard. When you apply for a visa you must state if you're a journalist or not. After that, a quick Google should suffice, especially if the articles written by her became popular.
I remember in the mid-2000s that online-journalists whose sites had millions of impressions per month were denied journalism visas because they weren’t traditional established print newspapers - then there was a debate about the difference between a blogger and a journalist.
I’d like to know if a non-journalist who maintained a very popular blog, such as an influential software engineer, who occasionally blogs about political or topical stories, constitutes a journalist or not. If they’re in the country for an industry conference but write about political events on their blog while they’re in the country have they violated their visa?
"The term "resident foreign journalists" means career journalists who are dispatched by foreign media organizations to be stationed in China for a period of not less than six months for news coverage and reporting."
http://www.china-embassy.org/eng/ywzn/mtyw/press_1/t944225.h...
A good question. Consider also that a blogger, lacking an influential institution such as Buzzfeed or the NYT at their back, may find themselves in much deeper trouble than a denied visa. Arrest, prison, espionage charges, etc. have happened to foreigners, including televised confessions:
https://www.nytimes.com/2016/01/22/world/asia/china-confessi...
After switching of The Great Firewall for ones own browser, that pesky thing blocks useful information.
https://www.nytimes.com/2016/04/07/world/asia/china-internet...