You don't have to work to hard to find a VIN. eBay, autotrader, or any parking lot on the planet reveals hundreds of them. As mentioned before, there's not a lot of reasons to post a VIN.
I think it would be of service to give tips in spotting fraudulent auction/item listing than protecting you're vehicle's identity.
For eBay
- Don't buy a car from some one with a feed back of zero.
- View the car before you buy it (aviod "immdiate deposits")
- Never even look at an auction that asks you to contact the seller first at a certain email address. Always use ebay's contact form first.
- Don't buy a car from a one day auction.
- Even if everything looks ok, contact the seller any way to establish any kind of communication.
If a theif is scowering message boards for VINs and pix, he's not very efficient.