Can an NPC use Diplomacy vs. the PCs???
I was wondering that a few months ago. I wrote up a Kothian Seductress and really bumped up her CHA and Diplomacy skill. The idea was to change the PCs attitudes into helping her out/going on missions (even though they might normally suspect she is up to no good).
...Yeah I know you guys don't trust her, but, she IS completely naked, giving you free booze and food, AND she rolled really well on her Diplomacy check...