Palgia;
What the others have said <G>, however, we are supposed to and normally do notify the watch desk if we show that you are overdue or if you disappear from our radar. In a perfect world SAR procedings would start after you disappear, however, as has been stated, we have a LOT of VFR's who just quit paying attention and go off into lala land while getting advisories. They quit talking to us as well as sometimes then going into areas of non radar, so that we can't follow them anymore.
That said, there is nothing written that states that we must do any kind of SAR procedings if we lose radar and radios with you. Will we do this? I would say that we will start looking around for you, but this will be determined by just how busy the facility is at the time... Your best bet is filing a flight plan, but I have found that doesn't always work either, since I have called to cancel VFR flight plans and had AFSS not know anything about me <sigh>. For backup, I would always have a family member or friend know what route you were going to take and where you were going just in case you don't show up...
regards
Scott