Green Knight
First Post
As a DM one of the skills I truly hate is Sense Motive. IMO, it's pretty unrealistic for someone to be able to determine for sure if someone is lying just by looking at their gestures and facial expressions.
Funny, because that describes a scene in one of my favorite movies, 'The Negotiator'. While it played a little bit loose with real neurophysiology, the underlying idea is the same. You question somebody and you study their tells and you can soon figure out if they're lying or not. Point is, Sense Motive is completely realistic. Just because you and I aren't astute enough to notice the small details that indicate a person's lying doesn't mean others can't. Anyway, if your players are using it to their benefit more then you'd like, then you might want to start writing up NPC's with ranks in Bluff. Opposed rolls, after all. It isn't a set DC one has to meet for Sense Motive to work, which means that the difficulty for Sense Motive should scale up as the bad guys do. Not to mention that, as others have mentioned, there're modifiers that can be applied to the DC. Plenty of options there without having to houserule it or fudge the rolls.