I should add the following to my post above. Even though I have a user in my Admin group who has not logged onto the board since 2006, I get the following results when I run the cron job manually:
Inactive User Reminder Emails
Done
Looking at the php code, it appears that it should say:
Inactive User Reminder Emails
mailing
test@test.com (done)
Done
but I don't see anything in between the lines even though clearly this test user i set up does qualify for a mail according to the parameters I set up..