[Tainan]

Some "theoretical" answers to your questions:
#1 - It is a possible explanation of what has occurred.
#1a - Most likely ...no. See next answer for why.
#2 - The PRC/PLA does have a veritable "army" of computer techs working on all manners of intel intercept on hardware and via the internet. However a much more likely scenario is that your HD will be shipped to a company there in the USA where it will be tossed on a pile of hundreds of other "failed" HDs for eventual inspection and 're-manufacture.' These 're-manufactured' HDs are then sold in lots and made available on the market at a discount or in 2nd/3rd world countries at a much reduced price.
Its during the 're-manufacturing' process that the interspt of any 'sensitive' or interesting data would/could be found and 'mined.' Data Mining is a very hot business. If something of interest is found - thats where it gets tricky. Who would it be of interest to? Why would they want it? What could the finders sell/trade this intel for?
See the pattern here?
Maybe it would be something of interest to other crminal groups...Russian mafiya...Colombian rebels...Al Quieda terrs...Can money be gained through the use/sale/ or application of any data mined from this HD?
This is the motivation for data theft most of the time. Political motive tend to rank lower than monetary motivation.
#3 - Could be. Built in product obsolescence is not unheard of. That's a consideration. Make every 350th unit go bye-bye after a certain date. Its possible.
The poster with the USB key idea is on to something.
As is your taking the thing apart and seeing if the HD itself is damaged. Some good suggestions by the aficionados on FR.

By the way, its most likely your HD will get re-cycled by a company there in the USA rather than being sent to the PRC. Computer and parts recycling is a medium sized business and very competitive. The 3rd world wants technology they can afford.

[poiuqwer]

That's the best response I've gotten yet. I have taken apart four broken USB drives now, and swapped them into working boxes, and all drives work. By the time they break, the newer models are are bigger and better. So I just crypto-wipe them and stuff 'em in a cabinet.

I also have a disk array of, originally 750 GB Seagate Barracudas that had 5 year warranties. They were a couple hundred dollars when I bought them. That adds up. With the warranty, I just return them. So far, I've returned three drives. They do not have any useful information on them as individuals. But when two drives failed recently (a fan web out and some overheated), I began to think. Two drives constitute a recoverable strip. These are bad disks -- not USB ports. I'm just projecting the thought process on the USB drives. But what about internal drives on an array?