Real time physical custody is an important determiner on where the child should live if a parent asking the court to allow them keep custody of the child elects to move.
The key case controlling move away cases In re Marriage of Burgess (1996) 13 Cal.4th 25 held in its decision that the trial court must have a review of the custody arrangement to ascertain the best interest of the child(ern) if a joint custodial parent objects to the move away of the child to another geographical area.
Keep in mind that having the "joint physical custody" language in a court order by itself does not control whether or not the court will review the child's residential change from the backdrop of what is in the child's best interest. There must be in fact a joint custody arrangement.
In a recent unpublished case, the California Appellate Court held that where a mother had a stipulated order awarding joint legal custody and had the child primarily with her until her relocation to another state, she was not entitled to take the child with her. In this particular case, mother moved to Hawaii leaving the minor child with her 24 year old son in CA. In 2008, father filed a motion for custody of the child and mother responded that she moved to Hawaii expecting the child to relocate with her.
The trial court determined that by leaving the child with her adult son, mother abandoned her role of primary caregiver. In this case,the child had been mostly in mothers care before her departure without the child for Hawaii.
Mother unsuccessfully tried to argue that since the child had primarily lived with her since 2003, father should not be entitled to a hearing on the child's best interests and that because she primarily had the child up to her departure to Hawaii, the court had to allow the child to go with her. Mother pointed to dad's stipulation that, in fact ,the child had been primarily living with mother since 2003 to support this position!
The appellate court supported the trial courts change of custody to the father because mom gave up her position as being the primary caretaker of the child by leaving the child with her adult son.
By having the child stay with her adult son, mom could no longer claim she was the primary custodial parent and that dad was not entitled to a hearing on the child's change of custody to his care.
What all of this really means is that each formal or informal change in a parenting relationship will trigger different legal outcomes if the parents dispute the custodial placement of a child. If you are contemplating a move or even a significant change in what you believe is visitation time, it is always best to consult with an attorney experienced in this complicated area of family law to better understand you and your child's legal rights.