Looks like the Chinese are controlling access combined with the fact that the Obama administration did not "invite" any US journalists to accompany them on the first lady's plane, and she's not giving any interviews.
Washington Post
The situation is further complicated by the difficult media environment in China, where the communist government controls much of the media and negotiations between officials from the first lady’s office and the Chinese agency that oversees media access have been visibly contentious. Chinese press officials have shoved U.S. reporters around physically at some venues, prompting objections from Obama’s staff.
Out of four overseas trips without her husband, the first lady has traveled with a press pool once — in Africa in 2011. East Wing officials say the plane she uses on solo trips is much smaller than the president’s Air Force One, making it difficult to accommodate reporters.
Still, there are reporters there and they are writing about the trip, esp. the Huffington Post. :laugh: