Has anyone noticed that chaff only affects players - so if you're taking fire, your chaff spoils your agressor's aim. If you're giving out fire, the NPC's chaff spoils your aim.
However, when an NPC drops chaff, other NPCs' fire seems unaffected. At first I thought it might just be that they were using fixed weps, but last night's ultimately disastrous blast around an RES showed NPC beam turrets landing perfect shots on my target while my gimballed pulses were dancing.