Here's a quick guide I made to find out if a scarf is real or fake.
First of all; the pricetag. Alexander mcqueen pricetags come in two sizes (sunglasses got different tags, if you want I can upload pics aswell). There's a tall one and a less tall one

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As far as I know the tall ones come with scarves and accessories, the less tall ones come with clothing.
The back of the pricetags should look like this:
Sometimes a plastic bag is included, if there is this is what it should look like:
Also the cord should have a "c" inside of a "Q".
NEVER will there be "mc" inside if the "Q"
Can't say too much about the tags on the scarves itself, they come with different stitching but should resemble the following:
Some scarves have "alexander mcqueen" printed on them aswell (not all scarves though!) when this is the case the "A" should be aligned with the "M" and the "R" should be aligned with the "U"
Sometimes you will encouter a MCQ Alexander Mcqueen scarf. The is an underline of Alexander Mcqueen and isn't made by the famous fashion house. Though they have some nice items (I personally own 25+ MCQ items) and they are very affordable. Keep in mind that also these items are being replicated. The tag should look like this:
MCQ Alexander Mcqueen items will
never have trademark symbols like the skulls on it!