I'm still thinking that if one parent is deceased, the game changes. I'll dig around and try to find some Calif case law for us on the topic :)
cites: Case Law, Grandparents Rights, Rulings
http://www.usatoday.com/news/washington/judicial/2006-09-12-grandparents-favored_x.htm
The court also emphasized that Pennsylvania’s visitation statute was unlike the broadly written Washington state law at issue in 2000, because Pennsylvania specifically gave visitation rights to grandparents whose child had died.
http://family.findlaw.com/child-custody/custody-more/grandparents-visitation-rights(1).html
Many states have permissive visitation laws similar to Washington’s. These states don’t see grandparent or caretaker visitation as a severe restriction on the right of parents to control the upbringing of their children.
Instead, they classify visitation as only a slight burden on that right. Therefore, the states need only justify the burden with a “rational” reason. Preserving the right of
children to maintain strong bonds with their grandparents generally qualifies as such a reason.
http://family.findlaw.com/child-custody/custody-more/state-grandparent-custody.html
California Conditions for grandparent visitation rights include a determination of whether a parent is deceased, the child’s parents are divorced or separated, the whereabouts of one parent is unknown, or the child is not residing with either parent. In addition to determining that visitation is in the child’s best interests, the court must find that the grandparents had a preexisting relationship with the grandchild. The court must also balance visitation with the parents’ rights. If both parents agree that the court should not grant visitation to the grandchild, the court will presume that visitation is not in the child’s best interests. Adoption does not automatically cut off the visitation rights of grandparents.
Kentucky: A court may award visitation rights if visitation would be in the child’s best interest. A court may award a grandparent the same visitation rights as a parent without
custody if the grandparent’s child is deceased and the grandparent has provided child support to the grandchild. Adoption cuts off the visitation rights of grandparents unless the adoption is granted to a stepparent, and the grandparent’s child has not had his or her parental rights
terminated.
also:
http://www.californiafamilylawblog.com/2006/11/for_grandparent_visitation_thr_1.html