Pet Custody Battles
I have seen two cases that dealt with pet custody and both of them were bad. Legally, it is quite a lot like children, but I think people can be even more irrational about pets, when they are upset.
I agree that family members usually know who the pet's owner is, but I am not sure getting them involved to resolve the matter is a good idea. I also would not counsel family members to "lean" on the person trying to take the other person's dog away.