I bought a record from a guy on eBay and it was rated at NM, but when I got it, it was warped. There are many factors to be concerned with when properly grading an LP for a customer, and being warped removes it from the NM category.
Scratches and abrasions are the easy thing to grade, but there is also the warp, off-concentric spindle hole, flashing around the spindle hole, over-heated pressing (which is next to impossible to see visually), and a whole bunch of other things I can't even think of right now. Near Mint means it is damn close to perfect, in my books.
So, perhaps the moral to the story is that one persons treasure is another persons junk. Grading of used LPs is purely subjective and the real story is "buyer, beware".
Wayner