There is a difference between knock-offs and non-official retails sales. I've bought from Sound Luck store in Shanghai and everything appears legitimate. They're just not an official store so they are able to advertise and sell below MAP. This is legitimate anywhere in the world, including the US, though manufacturers have been known to deny warranty work. Ironically, of all the manufacturers I buy from, it's Apple who has the most open costumer friendly policy. I've had people buy new iPhones in HK off the street for new released sold out phones and Apple fully honored all warranty work in either China or US. The worst that happened was Apple back dated the start of warranty to when the device was first sold by the official channel, so you lose a week or two of warranty, since they do not accept proof of sales from non-authorized vendors.
Though I will 100% agree there are a lot of fakes/knock-offs on Taobao so one has to be very careful. That's why for more expensive items I will go and inspect from the store.
In the case of Poly and Sound Luck (and many other similar audio equipment store), it just seems they've been too eager to sell a new product and jumped the gun. Just a week ago a bunch of places offered Poly for sale without stating its pre-release (and this is against Taobao policy). I've noticed today all Poly listings are gone. But you can find Hugo, DAVE, Moly ... etc.