I haven't seen the scene you're talking about but it might be possible since Lost and this film were both being filmed/made circa 2004 and like you said, both in Hawaii. I'll have to look out for her the next time I see this film.

I just came on here to check that myself cause I also swear I saw her in the background too. So you're not the only one. She isn't credited in the movie. This movie and Lost are each filmed in Hawaii so it makes sense that maybe she was on set that day and they put her in as an extra for fun. For an extra she was very much deliberatly in shot (and looked at Adam Sandler) so I think it may have been intentional to give Lost a little publicity.