Detection System

Players who are carrying contraband, magical or otherwise, are subject to the detection system when traveling in cities. It's important to know that that only creatures that are carrying contraband are subject to the detection system. 
Your detection score is determined as follows, 8+your passive disguise modifier+ 1 for each magical item - your dexterity score.
As you move through the city, members of the guard who are looking for magical items will be making checks against your detection score. 

Guard Type	Modifier
City Watch	-8
White Guard	+3
Bojistani	+4
Inquisitors of Thought	+5

Additionally, some guards are assisted in their search by the spell detect magic, these individuals will immidiately be able to spot contraband within 30 feet of themselves unless you are protected by a material barrier as stated in the spells description.