[Russell Sobie]

They probably aren't copying your skins... they simply click on available liveries on their hard drive. It's simply pointing to the directory with your name on it. I've taken to making my preview.jpg to include a bunch of text to make it clear that my skin is for Russell Sobie, and if they want their own skin, hit me up on the forums.

Unless of course they are literally copying your directory and renaming it to their name... in which case... wow, that's lazy.