Yesterday we reported that Modern Warfare 3's Elite maps are locked to a single Xbox Live profile, which means that other Gamertags on the same console can't access the content despite it being guaranteed in the Xbox Live terms of service. It seems that this state of affairs was an accidental error rather than a purposeful lockout, and Infinity Ward have promised to fix the issue "as soon as possible." More details below.
In a statement to Joystiq, Infinity Ward's Robert Bowling confirmed that the profile lock was an unexpected error and that an update is in the works.
We understand that ELITE Premium Members on Xbox Live who purchased the latest DLC Content Drop for Modern Warfare 3 are unable to access that content while signed into other profiles on the same console that originally downloaded the content. This is unintentional and we will work to get an update out as soon as possible that corrects this issue and allows you to continue to enjoy the new maps.