We don't need to introduce Bower & Wilkins (B&W) speakers. Those speakers are considered today the reference particularly in high end series like Nautilus.
The fraud concerns mainly the Nautilus 800 series: 800, 801, 802, 803, 804 and 805.
If you find an auction proposed by a newly created member in England or China, be carefull. The price is often very attractive and far from the usual market price. The seller most of the time does not propose a payment method and they are just waiting that you contact them to know how to arrange the transaction. Those people will ask you to send money via Western Union and you will never receive your speakers. You have to know that people don't have to show their passport or ID to Western Union office, they just have to give the reference you gave them. Because Western Union is present everywhere in the world, even if you thought that the member was in China, he is perhaps just in the house close to yours :). There will be no way for you to get your money back and to find the thief then be aware...