That's why I posed my question, though. If they were that vigilant there wouldn't be 50+ active auctions (not counting those that have already sold) of custom Vinylmation featuring Disney characters on them. It's not that difficult to find them on eBay. So, something tells me that what the customizers are doing is legal in some sense.
If they're taking a blank "canvas" and putting a Disney character on it, without Disney's permission, then they are absolutely violating copyright law, in every sense (unless it falls under the very limited "fair use" portion of the law, but I can't see how these would do so). Now, it may be that this is what Disney actually wants people to do with those blanks, and there is express or implied permission given to do so. Or it may be that Disney has some other reason for not stopping those auctions. But you should never assume that use of a copyright protected character is legal simply because no one has put a stop to it.