For me, the only real way to tell is to ask the seller for a clear picture of the tag that's on the scarf.
Here's a handy "how to tell real from fake" guide that I posted based on scarves that I purchased:
http://forum.purseblog.com/the-wardrobe/mcqueen-skull-scarves-how-to-tell-real-fake-247178.html
Here's a handy "how to tell real from fake" guide that I posted based on scarves that I purchased:
http://forum.purseblog.com/the-wardrobe/mcqueen-skull-scarves-how-to-tell-real-fake-247178.html