Courtesy notices bouncing

[Eric Rhee <erhee at chulavista dot lib dot ca dot us>]

Greetings - I am getting bounced e-mail courtesy notices sent to me from our
spam server.  The curious part is, they are for people who don't have an
e-mail address in their patron record; no "z" e-mail field in their patron
record and nothing that resembles an e-mail address in their record.  I'm at
a loss to understand and fix this.  We are not printing and mailing courtesy
notices.  Can anyone explain why this is happening and how to fix it?