The reason is this: al-Qaeda terrorists had made 8 attacks on the Chinese with the following results:
One person was to explode a bomb in Beijing Xizhimen (the main northwest gate of Beijing) but he lost his way in the three-dimensional traffic bridge;
One person in Shanghai was directed to take a bus to explode a suicide bomb in the bus, but it was so crowded he could not get into a bus for two hours;
One person was to bomb a supermarket in Wuhan, but found that the bomb remote control was stolen;
One person wanted to bomb government buildings in Chengdu, but was stopped at the door by the security staff and arrested as an East Turkistan separatist, and was beaten and interrogated;
One person succeeded in bombing a Hebei mine, with hundreds of people dead and wounded, and then returned to the al-Qaeda center, but even after six months, failed to see any news reports on the success of the bombing， he was considered by the organization to claim a false victory and was executed;
One person had tried to bomb Guangzhou, but as he came off the train, a motorcycle robber (flying car robber) snatched his bag (containing the bomb) from him;
One person who arrived in Xi'an lost contact, and was later found at the hospital in a state of coma. Doctors said it was the result of him eating not only harmful food products, but he also drank fake alcohol;
Later, bin Laden tried to send a female terrorist to blow up Hainan Island, but she was cheated into prostitution!
Finally, Bin Laden conclude that China is the only country which cannot mess with!