The SAR situations with which i am familiar involve trained civilian volunteers working under the local county sheriff. A designated deputy was the individual who initiated the search, and managed the search. Thus legal authority was available, if necessary, to dissuade overeager volunteers, and occasionally to deal with associated criminal activity.

Usually that wasn't necessary since you could find some productive tasks for them (base camp chores, low risk areas, etc). I think we snagged a few members in this manner, as well.

Don't discount working at base camp. On the typical operation which lasts less than twelve hours or so, base camp is pretty minimal. But if the operation endures, base camp activity expands and becomes increasingly critical.

Concerned friends and relatives of the missing persons are often valuable in another regard. They can provide insight into habits and tendencies of the lost persons. This can be crucial in shaping the search effort.

You soon learn to be discreet in your comments in and around BC, and on the radio, because you never know who is present....