Other policies can be highly local, for example, health coverage could
easily be done on a
state or even county level without an easy way for the policies
to be circumvented - sure, people can
move to a
different state / county but what counts as a policy in this case is the obligation residents have
to pay in
to the system and what their benefits are from it, so
moving from
state to state would not subvert the policies, it just changes the number of people subject
to these policies.
If there are delicate issues involves, such as abuse or if one of the parents wishes
to move to a
different city or
state, a child custody battle can very quickly and
easily get costly, both financially and emotionally.