Can an under age be blame for having with a man over 18?

No its his fault because 1 its illegal to film someone have without permission and 2 if they are over 18 and the person is 16 no 18 than yes because he's officially an adult where she is allowed to consent, it's called statutory . If she 18 or over then its legal but the fact hes a full legal adult then no its wrong. This is Australian law i don't know where u are from though? But if he showed it in court he wouldn't win he would just be showing proof he technically d her.