No, she wasn't high... just not used to this type of stuff. Con is pretty hectic, with a million people pulling you in a million directions, and that, coupled with the fact that all of the cast is incredibly tight lipped about this movie, meant that she was simply nervous about giving too much away. I interviewed another female cast member, and she wouldn't even admit that Jason kills people in the movie! Hopefully once the movie is closer to release the interviews with cast/crew will be a bit meatier.
Also, keep in mind that the interviewer may have been trying really really hard not to gawk at Ms. Righetti and thus maybe kept losing his train of thought. You know, hypothetically.