Fair call Griffo ! - If this was charter operation could you have an Ops Manual that allows you to depart on a fairly long flight with no flight plan, or flight note left, and for the operator to not know at least POB ?
Basically as such you have no idea who it is, how many people, and a real idea of where they even 'could' or might be. Really feel for the guys in Canberra at AMSA trying to co-ordinate a rescue with no information to go on when it's peoples lives and loved ones you are talking about !
No info you would assume it was VFR as well ?