JoeGKushner said:
Only role playing in such a case will usually only lead to downfall if your players have the right skills because their skill totals will be much, much higher. "Yeah, I bribe the family into allowing me in to kill X. My diplomacy is 32 and my sense motive 28."
I think diplomacy +32 doesn't necessarily mean you can get anyone to do what you want - not without telling the GM
how you are going to proceed. If you want someone to go against their ingrained beliefs and their duties, you will need to come up with a good reason why they should do so, no matter how high your diplomacy skill is - and that's roleplaying.
The advantage of high diplomacy bonuses is that you can use much flimsier excuses, and present them much more convincingly, than people with lower bonuses. And high Sense Motive bonuses will give you a much better idea about what stories might work.
If one of my players simply told me: "Yeah, I bribe the family into allowing me in to kill X.", I wouldn't even allow a roll. He isn't role-playing at all, and the best he could hope for is that the family doesn't
immediately call for the watch.
However, if he says: "I engage the family father in some friendly general chatter about the city and gradually try to find more about his family's financial situation.",
then I'd allow him to roll against his epic Diplomacy and Sense Motive skills to find an opening. While someone with +0 in both wouldn't get far without
exceptional role-playing, this guy can probably easily convince that he is "only going to play a harmless prank on an old friend, and here is something for your trouble." While the family father probably knows at some level that he is doing something wrong, the Diplomacy skill allowed him to bury his doubts deeply in his mind. Later on, he will tell the Watch that he was quite
shocked when he noticed the dead body in the morning. He might even believe that himself.
In summary: Skills don't substitute for role-playing, they complement it. Or at least that's how I handle things, and I am sticking to it.