Discreet packaging is what they will use.
Customs is not going to open every package coming to the US from China that says "electronic parts" on it.
This will only work if the overseas manufacturers use drop shippers.
The information on today's shipping labels can identify a vendor by
location shipped from in most cases. Things like billing info and,company
name would have obscured in some fashion.
Then there is this,
point to pooint shipping solutions - Google Search with humongous files of data.
I do not know if China has something like our zip codes but,there large shippers
must have something similar to track and properly bill shipping. I am assuming
that if the government gets really serious about blocking imports it will not be
a big deal.
As far as the Chinese government is concerned as with most any other government
if one country restricts imports of certain items it is 'generally' agreed on to be
cooperative in these manors if asked. Check UPS,Fedex and the USPS list of items
not to be shipped listed by a countries laws. One item that sticks out is religous
materials. If the Fed's wants it restricted it will be to a great extent. Not immpossible
to get but, It will take some doing and increase cost's.
Regards
Mike