We maintain a separate directory with information that helps me determine if someone belongs in a group. I use @ExpandNameList to grab all the members of a particular group to make my comparisons. I ran into an issue where it was saying that someone belonged in a group, but placing them in that group resulted in them still being flagged as needing to be in the group. For example, the group's members:
Suzie P/MyDept/MyCompany
Bill Nobody/MyDept/MyCompany
The routine came back saying that Suzie Q/MyDept/MyCompany should belong in this group so I changed the group to have members:
Suzie P/MyDept/MyCompany
Suzie Q/MyDept/MyCompany
Bill Nobody/MyDept/MyCompany
Still said that Suzie Q should be in there. The issue was that Suzie Q got married and her name changed to Suzie P. Despite having both names in her address book entry, @ExpandNameList will only return Valid *current* names. Her name needed to be changed in our locally maintained directory.
I now have newfound respect for this undocumented function.