Two Negatives Make a Positive?

Although not uncommon in everyday use, in our class I would suggest we not use two negatives to make a positive without good reason. These two links discuss the subject of double negatives and give "litotes" as a good reason.

• Grammar Book, a resource for grammar and punctuation states that “To avoid confusion (and pompousness), don't use two negatives to make a positive without good reason. Sometimes a not un- construction may be desirable, perhaps even necessary: Example: The book is uneven but not uninteresting.” GrammerBook also quoted “…novelist-essayist George Orwell warned of its abuse with this deliberately silly sentence: "A not unblack dog was chasing a not unsmall rabbit across a not ungreen field." 
• Merriam-Webster's online dictionary, a recognized conservative dictionary, defines litotes as an “understatement in which an affirmative is expressed by the negative of the contrary (as in “not a bad singer” or “not unhappy”)”
  
  
  When writing we need to keep our site visitors in mind. The use of double negatives may cause our visitors confusion, making them pause to think about the meaning of our intended statement.