Lead. You are correct however there was nothing to stop the old Sar watch system being given by ATC Not FS.
Most pilots believed that if you missed a full position report that within 2 minutes they would start a search.
During our AMATS research we found out that due to lots of position reports being missed due to radio and other problems that it was more likely a search would not start until planned fuel was exhausted. The extra safety was a delusion!