Email Optional setting under General

Currently under the General Settings category, there is a checkbox labeled "Member Email Optional" which does not work as expected.  Based on the label, one would assume that if not checked, then email would be a required field for all "non-child" roles including Primary, Spouse, Other Adult and no role.  For child roles, email would only be mandatory if the checkbox "allow login" is selected.  This is the functionality that we need.  Currently whether the "Member Email Optional" box is checked or not, the email is not required.  It is not clear what this setting does as it is currently coded but it is not useful.