Maybe, maybe not. Someone I know who seemingly leads a normal social life turns down all my invitations to hang out with groups because he "doesn't need to meet new people." And he's not the only person I've known who has that attitude.
Sure, that's why I said that I can't know for sure - because it's a sentence that can be used truthfully or it can be used as a polite lie.
I just feel that if it were possible to track every time that sentence is said it would probably be significantly more often used as a polite excuse rather than as a truthful statement. (And even then, that's my gut feeling / assumption, I may even be wrong about which use is more common).
