Though you have to agree not all places would let you pass just because you ask nicely. You can't just flirt your way into area 51. Also considering that some places in Fallout use robots, it becomes even more unrealistic.
I agree shooting everything is unrealistic too and shouldn't solve everything, but charming your way out of everything is also unrealistic. Raiders seem to shoot first ask questions later, good luck using your charm on their bullets.
Also, slavers use non lethal weapons, and besides, talking instead of shooting is also un-american.