I don't know if "kidnapping" is the right word to use to describe this phenomenon I have been told happens in Wuxi. Thieves will steal license plates off cars, and then demand money (ransom) from the car's owner to return the plates.
My first question, of course, was how could the thieves get away with this? Couldn't the car owners contact the police so they could track down the thieves? It turns out that the thieves don't demand that much money for the license plates -- just 100 or 200 rmb. These "ransom" amounts don't make it worthwhile for the police to get involved, and are less expensive, in time and money for the car owner, than going through the process of getting another license plate.
I then asked how the payment of ransom was done. The thief tells the car owner to put money in his bank account.