Re: What about numberplates?
Perhaps against a number plate recognition algorithm, however against a car recognition algorithm less likely to be immune. First consider the dataset, as in how many of your car (same make, body shape and colour) were produced - except for the most popular car this number will be surprisingly low. Then consider any after market modifications, such as hanging ornaments (or their absence), stickers or even the odd scrape, some of which would require a relatively high resolution image, and your car is not as generic as you might think it is and therefore it should be relatively unique.