I honestly don't think she's doing anything for publicity. She hates being in the press and has since she was young. I think she's genuinely doing everything because she cares, no matter what happened in the past. Things happen, people make mistakes.
IF she was after publicity and wanting the world to know that recall that she was married to MJ then she would've put it out there what she left at his tomb instead of asking the fans to send flowers. She didn't put that out there. Some gossip rag did...
"X17online brought you the exclusive details about Lisa Marie Presley's initial visit to the mausoleum in which she carried in an empty portrait-sized frame filled with sunflowers ... spending over an hour getting the placement just right."
http://photos.tmz.com/galleries/michael_jacksons_tomb_with_sunflowers#tab=most_recent&id=69909
http://photos.tmz.com/galleries/michael_jacksons_tomb_with_sunflowers#tab=most_recent&id=69910
Judging by the inscription, I doubt she ever wanted to public to see that. That was for Michael and anyone who is lucky enough to be granted permission to see him in his final resting place.