Can covers be liars?

The fall publication of a YA novel called Liar by Justine Larbalestier is causing a stir in the publishing world because, as shown in this PW story, the cover depicts a white girl with long hair, while the book is about an African-American girl who describes herself as having "short, nappy hair". Obviously the publisher thinks the book will sell better if a white girl is shown on the cover rather than a minority girl. Is this a fair representation of the book? Is that even a fair question? Will the readers feel betrayed if they buy a book in which they don't recognize the heroine they expected to find? In the PW story, several bookstore buyers comment on the cover and their reactions to it, we'll have to wait to find out what librarians--and more importantly potential readers--think. The controversy certainly raises questions worth thinking about.