Weird.... But I wouldn't worry about "poor unsuspecting" customers... If someone actually buys a book based on the cover photo, then they deserve to get an unplesant surprise! ;-)
Bingo. The world at large will have no idea who the girl on the cover is. That doesn't excuse the historical mishap, but IMO, choosing an image from the wrong era entirely is more bothersome than the fact that they happened to pick Anastasia.
I agree that the cover of
Rasputin's Daughter is misleading as well as unsettling, but only to the few of us who recognize Tatiana.
Juliet's Moon, however, is not -- it's just plain inaccurate. Aside from the costuming issues, who exactly is this going to mislead, and how? Those who don't recognize Anastasia won't get the "joke" at all. Anyone who actually does realize it's Anastasia is only going to scoff at the incongruence between a Russian grand duchess and a Confederate flag.
Bottom line: I'm 100% in favor of historically accurate cover art, but anyone who's seriously trying to learn history through historical fiction ought to be redirected.