I agree with O'Shei and Turnoi.
I myself have four SIM cards at present. I have never encountered this problem.

And why bother with China Mobile? Just find one of those little shops or the ladies on the street corners near the China Mobile stores that sell SIM cards without any questions at all?

Some people like to register their sim cards in case of theft, but as I had said before, both of my 2 sim cards with a different provider were registered.