As part of the Call of Duty: Modern Warfare 4 announcement today, Activision unveiled what it called a “Loyalty” discount that will allow certain people to get the game’s $100 Vault Edition for 10% off. That’s not a whole lot, but it’s enough to offset the tax you’d pay, and in a world where seemingly everything is getting more expensive, it’s a notable discount if you want the more expensive version of the game. The discount does not apply to…