With the detection skill players are able to see members in the players' guild who are not actually members of their guild, but those who entered using the infiltration skill. By using an AOE (Area of Effect) Detect skill you are giving infiltrators an icon above their head.
How it works
Depending on the level of the players' detection skill they have a chance of seeing an icon above an infiltrator's head indicating that he/she is infiltrating the player's guild.
The chances of this icon appearing are lowered by their Infiltration skill. Successfully identifying an infiltrator will grant experience, and imprisoning an infiltrator will grant further experience.