I use to work for blue cross blue shield of New Jersey and I know you couldn't carry insurance for another person if they are not in some way related or is a dependant of some sort, but that was in New Jersey.True, true. I didn't even think about that. I still have a feeling that it will depend on what the insurance co. says, though.
Three years ago, my children lived with my ex-wife, and my wife (their step-mom) was able to carry them on her insurance.
I don't think there is a cut-and-dried answer to this question. Each ins. co. has their own rules and policies.