Correct.

If you have a GMRS/FRS radio, being the one in distress, you should transmit on every channel once in a while. Chances are the SAR teams are communicating with themselves using one of the channels.

There aren't really any standard operating procedures AFAIK regarding GRMS/FRS usage. I know that as a team leader, I might tell my people that have such a radio to use channel 3 or 4 to communicate, but this is only within this small team.

This does not mean that we don't use additionnal radios for other reasons. During operations, special antennas are put up that allow more powerful VHF radios to be used for the duration of the search.