Flying I've never had my bag even run through a scanner (8-9 times flying in) - unless they are doing it between plane and baggage collect, in which case they are really fast!.
Train, you run your bags through scanners, but no one seems to care (I've bought HEAPS of electronics in from Hong Kong ($2-4k worth at different times).
Beijing and Shanghai - I would say you are right, they seem to be a bit more uptight there.
In Beijing, they scan bags right before you get out to meet your loved ones. They appear to select people at random, and from my observation you have 5%-10% chance of being selected.
I'm not sure what they're looking for, though, as I've never seen them open a bag after it went through the scanner.
I was quizzed about my road bike (which was obvious as it was packed separately) but after I explained it was old, and 'just a normal bicycle' and not 'for competitions', they let me through without a fuss.
They are scanning all bags in Beijing these days, at least when coming out of T2 customs. I'm more worried about transporting it as,baggage in the first place. I'm just not a good yellow cow.
What happens if they find you have stuff that you have not delcared? I know for cheap items they charge you the tax or trash them. For several thousand dollars worth of equiptment though, they might not be so nice...
I could do it if anyone wants help me financially or with marketing. I've got many years of direct factory sourcing in China. First came here a decade ago and I've been living here for the most part of the past 3 years.
