Is Microsoft Punishing "Used Game" Customers?

Microsoft recently released the Gears of War 2 'Flashback' map pack for purchase on the Xbox 360 Marketplace. A voucher for the map pack is including in the Gears of War 2's case when the game is purchased new. It seems now that Microsoft is trying to make sure that they get their share of these extra earnings. This single deterrent may not hurt the sales of used titles but it could start a trend that may eventually affect your ability to find that not so new game for a truly cheaper price.