I've heard of companies that consider any electronics thats ever been taken to China to be no longer useable on the company network. Their approach is to consider those devices "disposable". If ou take a laptop to China, buy a replacement when you get home and give the old one away - its never to be connected to the internal network again.
At a previous job (.edu), we discovered a compromised host and shortly thereafter found that it was the laptop of a professor who had just returned from China.
