There is an interesting case called Care & Protection
of Emanuel in Massachusetts
that talks about the process where absent or
waiver meaning that the parents and child waive the right to a 72-hour hearing.
The court would first determine whether the custody of the children should be
removed from the child’s parents; or the present legal custodian or guardian.

The second part is to consider any nomination by either the
child or his parents of either a relative or another individual to become the
temporary legal custodian for the child while the care & protection matter
goes on.

Most courts now have a better understanding and typically
have a written waiver for parents to consider and children would also have
their attorney do a valid waiver. There is some disagreement about whether or
not the parents would have a separate 72-hour hearing regarding custody for
themselves and then after that 72-hour hearing if they are unsuccessful would
then have a home study done for the proposed 3rd party custodians.  Then a separate hearing or whether or not it
would all be intertwined in one hearing or different mechanisms that the courts
have.

It is important to determine whether or not you want to
waive your right to a 72-hour hearing for yourself or not; and if you do choose
to waive your right to a hearing for yourself whether or not you would want to
waive your right to a 72-hour for somebody that you would nominate and consider
all those factors or whether or not  you
want to look for a custody hearing for yourself and a 3rd party
custodian only unsuccessful or you would like both at the same time if the
court is willing.