The reason I asked is because I've had knowingly had unprotected sex with a Heb B positive person. I had had a successful vaccination (meaning the antibodies were detectable in my blood) and consequently never got infected from him.

He disclosed this to me before we had sex. I told him "no big deal" because I had the antibodies. So just because the girl is having unprotected sex and hep B positive doesn't mean she's irresponsible, as long as her partners have had a successful vaccination.

(It is important to verify that your vaccination "took" however, before having sex with a hep B pos person.)