The Asahi.com gives us some insight as to why this happened:
BEIJING--City authorities here, reacting to the row with Japan over the arrest of a Chinese trawler captain, have called on local travel agencies to refrain from aggressively selling and promoting tours to Japan.
The step appears to be a deliberate measure to express Beijing's displeasure with Tokyo.
Earlier, China shelved Cabinet-level contacts with Japan.
Japanese authorities arrested the Chinese trawler captain after he rammed two Japan Coast Guard vessels in waters off the disputed Senkaku Islands in the East China Sea.
The incident two weeks ago soured bilateral ties because both countries claim sovereignty over the islands, which Chinese call Diaoyutai.
According to several travel agencies, Beijing's municipal tourism authorities summoned representatives of dozens of tourist companies Tuesday night to request they be less assertive in promoting tours to Japan.
The request was made verbally, according to people who attended the meeting.
An official with a leading travel agency in Beijing said Wednesday that tours to Japan up to early October that have been already booked will go ahead as scheduled.
But the agency is not recommending tours after that because Japan-China relations remain so strained.
China usually has a huge display on board for the JATA World Travel Fair so they were sorely missed. But the folks at JATA did a great job working like crazy to fill a huge hole in display area that was left by an absent China. I would imagine that most visitors to the JATA World Travel Fair 2010 would not notice China's absence unless they were alerted to it intentionally.
It struck me as strange, though, that, while China did not attend, there were huge displays and exhibits by Hong Kong and Macau.
Mish of Global Economic Analysis writes: