Precisely! Exactly what I was trying to explain. This does not result in a long subject line because we are usually asking about one or two people at a time.
"My understanding of Marjorie's original post was that when posting a message about searching for some elusive relative, the subject should include the relative's name, rather than just e.g. "searching for lost relative".
I don't believe anyone in this thread meant you should put your names of interest in the subject line."