Mrs. Peel, you're needed. :)
I hate child molesters.
That being said, I think it wise to reserve judgment on this one until someone here has seen the film in question. Children bathing with adults is not necessarily wrong. In some cultures (Japan comes to mind) the practice of children and parents bathing or soaking together is part of traditional culture. Up until recently child nudity was seldom considered in a sexual context; a naked kid was considered by and large to be no more erotic than a “naked” cat or dog. Only in recent “enlightened” times, when traditional mores have been abandoned, have children been routinely depicted as objects of sexual desire in the mass media.
I advise caution. Ms. Kidman is known to be a devoted mother. Let's wait and see what's actually in the movie before we all freak out.