When massive lines of people waiting overnight in sub-freezing temperatures at Apple's flagship Sanlitun store in the capital city began to cause crowding problems -- and when Apple employees and Chinese security personnel realized that the vast majority of the queued would-be buyers were scalpers looking to purchase & then resell the in-demand phones -- the store opening was delayed. Angry linewaiters began chanting for the store to open, eventually throwing eggs at the store facade.
Now the announcement has apparently been made: no more queuing, and no iPhone 4S sales at the Beijing flagship store today. Other stores in the capital and in Shanghai apparently had no such crowd control issues, and China Unicom sent text reminders to subscribers that they could order the iPhone 4S for free home delivery.
Update: The New York Times reports that Apple has officially suspended in-person sales of the 4S at its China stores, although phones are still available from China Unicom.