Friadoc
Explorer
My thoughts on this are that if you cast Charm person on an 83 year old woman she is going to give you some cookies and a silver piece to get yourself a proper meal, not jump on you. Similarly, if you cast it on a woman who's not attracted to you, she's going to be giving you the "I don't want to endanger our [fake, magically induced] friendship" speech.
Charm person should be no more effective than taking someone out for a meal, with flowers, chocs and half a bottle of red plus some nice conversation.
But that may not be how its being used in the OP's games...
Afterwards of course, the target may (not entirely unjustly) feel they've been taken advantage of, if they work out what happened.
Is this worth a forked thread?
I don't think it's worth a forked thread, as it is related to the core situation of the post.
Charm Person is a lot more effective than a dinner date with some extras, a lot more. If it wasn't, it wouldn't be a spell.
Charm Person could take a person who thinks the character is an idiot, devoid of personality, and then make them someone that is looked at as a close friend or ally. While it will not make a character jump into bed with the casting character, it will put the character in a state where they are more inclined to listen to the casting character, be open to approaches of the casting character, and, thus, it is an external influence that inhibits the reasoning of the character.
If my character used charm person on a guard, thus making the guard friendly toward my character, thus more likely to turn their back on their trusted friend, then they would not see the sneak attack coming, would they?
Thus, if charm person is used, in conjunction with a silent spell, it is more easy to get a charmed character to trust and follow the caster, who cannot call for help due to the silent spell, thus is can be akin to rohypnol and other such drugs. Sure, they have good uses, but like with anything there is also misuse.