http://www.computergamesdb.com/club-nintendo-rewards/

Does buying Club Nintendo rewards reduce your coin count?
I was wonder if getting a reward from Club Nintendo reduces the amount of coins you have, subsequently reducing your status (gold or platinum.) I wouldn’t want to get one of the rewards with my coins only to find out I lost my status, and the special reward that comes with it at the end of the Nintendo Year. So does anyone know how that works?
I would assume if you use the coins you earned through buying games, etc, to get a “reward” that you would not keep the same number of coins you had- I believe you “use” the coins to get your reward, so they will not be valid any more.
Club Nintendo ‘09 Special Rewards