Different things can be meant by the word 'nonconformist'. Is it someone who doesn't care about conforming or someone who cares about non-conforming? The first kind of person will act weird as long as it doesn't hurt them too much but they will not engage in any norm-breaking that could put them in actual danger. They will even signal their harmless weirdness if they feel like it. The second kind will set out to prove to themselves that they are truly different and unique.

There are also people who feel strongly about being 'normal' and they also feel strongly about adhering to the cultural ideal of romantic rebelliousness that you talk about in your later comment so they will indeed seek cheap ways to signal nonconformist traits.

I read SarahC's comment as referring to nonconformists of the first kind, while from your comment I got the impression that you divide the space of weird people into 'true nonconformists' who seek weirdness for its own sake and pseudo-conconformists who really want to fit in but at the same time try to give out a rebel vibe.