It looks like this has been mentioned on the TDI club forum before (http://forums.tdiclub.com/showthread.php?t=280368), but a quick search turned up nothing here on the vortex.
Just purchased a CPO'ed 2009 JSW and upon detailing it (dealer did a worthless job), I noticed that the dealer-installed screws for the rear license plate are too long and the self-tapping kind and are jabbing into the body of the lift gate. There's four small rust spots now that are through the paint and it's bubbling around a couple of them. Awesome. Here are some pics:
The extent of rust makes me think that this was likely caused during it's previous ownership (other than the nice fresh primer that can be seen in the upper left and perhaps the line in the lower right). It's definitely not a simple clay/touch up job at this point. I plan on calling the dealership tomorrow morning and speaking to the GM, as I certainly would not have bought this car without it being fixed. I was quoted $300 by a reputable local shop, but they recommended taking it to the dealer/VWOA first. Let's see what the dealer GM has to say.
Check your screws!