in that picture, the ruler does not look on top of that fret, rather, the ruler is sitting on the outside edge of that fret, plus the ruler is tilted slightly towards the headstock.
get the buyer to send you a picture as shown in the below article, of an at least 24" ruler laid lengthwise to see where it contacts the bridge. that tells a lot quickly. if he will do that, notice the saddle height and bridge thickness(to see if either appears lower than they should.
here you go, an excellent article with pictures
http://www.frets.com/FretsPages/Musi...neckangle.html