What has been described tends to be laziness on the sellers part if they have a large stock of the item. The 'new' items get sold off but there will always be returns. These returns are then separated depending on their condition (box and packaging as well). Sometimes a buyer makes a mistake and returns the item untouched. Such an item can be relisted as 'new' because it has not been tampered with but if the box has been opened then it should be re-listed as 'used', even if the item was never removed from the box because as soon as the tape on the box is broken, it automatically becomes 'used'. Now when the stock levels start to get low and only the returns are left in stock the seller should change the listing from new to 'used' or 'refurbished' and mention so in the listing description.
Labels all over the book implies to me that the item is a return, it was sent out, got returned for whatever reason, put back into stock and then shipped out again when sold. If the item was the last one in stock and it was a 'return', the seller should have changed the listing to 'used' and should have mentioned that fact in the sale listing. If the seller did not do this and left the listing as 'new' then the seller has broken not only Amazon listing/selling practices but probably the countries selling laws.
I've had similar happen to me BUT in my case, even though the listing said 'new', in the listing description it stated that stock was down to the last few which were 'returns' and even though the product had been fully tested, the box/packaging would show signs of previous use. The price was also reduced because in many countries it is against the law to sell something at 'new' price when in fact it has been 'used' because 'used' commands a lower price.