I cannot emphasise this strongly enough: high Charisma always grants social privileges; low Charisma is always a social handicap. It is the job of a DM to ensure that that is the case: and that the low Charisma character suffers as a result.
Again with the 'suffering'. I am just curious whether you go after the PCs with the 8 Dex, Str, or Con - or do you consider their mechanical drawbacks to be sufficient? Your argument also assumes that someone can gauge someone's Charisma rather quickly upon meeting or speaking with them for a short time - I don't think there is such a mechanic; given 3.5's focus on charisma
not being tied to looks, I find this to be a stretch.
My problem boils down to this: If a character with a low stat in any other ability mis-roleplays as if they had a higher score, it would eventually come out. For instance, if the fighter decided to play a quirky character and only had an 8 Con, but blustered about as if he was extremely tough, during the first fight it would be very apparant that it was not the case.
However, if a character with an 8 Cha blusters about and is arrogant (which could be defined as low charisma, if it generally led to poor reactions) and I ask him to roll a Diplomacy check to not insult someone (or some similar social roll) and he rolls a '20', he has effectively negated that low score in that situation.
I bring up those 2 examples (8 Con Fighter, then it was actually and 8 Cha Wizard) because those have both occured in games I've been in. The wizard only met with the king that one time, and while the court hated him, the king didn't so despite his low Cha he was the intermediary with the king (which never came up again, except that he regularly insulted couriers bringing us information from the king).
I wasn't DMing either of those games, but I did play in them. I don't feel the DM was particularly unfair, a '20' counts for something in our games and the wizard rolled right when he really needed it (the DM later explained that he would have thrown the wizard in shackles for a day if he had rolled poorly and insulted the king).
Generally the wizard got by fine - 1 member of the party bought and sold our items, and the paladin 'leader' was usually the go-between for NPCs. The wizard never desired social titles, he had fun being a prick to the NPCs (though never enough to face repercussions).
I guess my consternation is what could have been done differently? The wizard was just below average in terms of charisma (8). How many penalties (or roadblocks) would you have put in his way for something the game mechanically penalizes by a -1 to social skills. The wizard actually did have some ranks in bluff (cross-class).
We did not have perhaps as many social engagements as other campaigns, but it was understood that the only PC interested in doing such things was the paladin, who himself wasn't that interested (he didn't want to have his 3 friends sitting around waiting for him to get done prancing around). We went to banquets honoring us, were lauded as heroes, etc etc. My advice to the Fighter with 8 Con was that the next time he had to put an 8 somewhere, stick it in Cha (the fighter died in the 3rd session, trying to tank a monster). I don't see how my advice is faulty, given the nature of the game.
Technik