Originally Posted by
STS-134
Leave it to China to put useless laws on the books though. If one is going to place a bomb somewhere and detonate it by calling or sending an SMS to a SIM, one can just as easily do it with a foreign SIM that's doing int'l roaming. Or with an old fashioned timer.

Contrary to your belief, this measure is not about preventing terrorism, but instead about controlling information flow.
This is also why FB is banned as well.