From what I've noticed, the fake stuff comes with tags but is missing the barcode sticker all together. I've also noticed (what I believe to be) a lot of fake scarves and hoodies on ebay that ship out of Canada.
I have three LAMB scarves -- two are directly from LAMB, the other one was bought off eBay a couple years ago. At the time I wasn't aware of any fake LAMB scarves, but I think it's possible that it may be after realizing it shipped from Canada. IF it is, it is an excellent knock off, which I believe a lot of scarves on eBay are -- this one is the same quality as the ones bought directly from LAMB. I'm not a supporter of knock-off anythings, but if the price is right on a scarf that you love, I say get it, because I don't think you can tell the difference -- but if you're unsure of the authenticity, I wouldn't pay too much for it (personally $150 seems a little steep!).
Hope this helps!
Totally agree! My friend got me one off ebay for xmas. It's my only LAMB scarf. Had tags so pretty much sure it's a fake. But, it is super soft and I love it! Plus, there was a serpent one (not fake) for $300 and this one was around $50. For some reason, a fake scarf doesn't bother me like a fake bag would. The quality is still great on it. Not endorsing fakes AT ALL, but I would have never got one, and I was surprised how good the quality was when my friend got me it for xmas.