Anybody careful enough should check the eSeller's feedback as to tell fraudulent and trusted sellers apart.
There is a nice website which will throw any negative feedback of a seller at you by just launching a search on the eSeller's name. [
http://www.toolhaus.org/].
Most of the times by just looking at the ridiculously low prices for high capacity memorycards you can tell they're fake anyway.
eBay also have their own list of trusted sellers for memory cards.
So, no thanks, no advertising is required.