User blog comment:Aegis Runestone/Does anyone else dislike Lucy being... *spoilers*/@comment-77.177.100.78-20120415031202/@comment-4636255-20120415084543

I think Eagle Vision doesn't tell freind from foe. Instead it tells us whether it will be beneficial or harmful to kill someone. So friends are blue and enemies red. But if an enemy's presence is actually beneficial, he is shown blue.

Example:

• Al Mualim led Altaïr to nine other Templars, and made him humble. So Eagle Vision saw him as a friend until he intended direct harm to Altaïr.

• Lucy helped to lead the Assassins to one Apple, and was useful to the Assassins as she knew some passwords of Abstergo. So Eagle Vision saw her as a friend, until they found the Apple, affter which she was to betray them.