diff --git a/ietf/utils/mail.py b/ietf/utils/mail.py
index af75cd835..34ecbba96 100644
--- a/ietf/utils/mail.py
+++ b/ietf/utils/mail.py
@@ -144,7 +144,7 @@ def send_mail(request, to, frm, subject, template, context, *args, **kwargs):
     return send_mail_text(request, to, frm, subject, txt, *args, **kwargs)
 
 
-def send_mail_text(request, to, frm, subject, txt, cc=None, extra=None, toUser=None, bcc=None):
+def send_mail_text(request, to, frm, subject, txt, cc=None, extra=None, toUser=False, bcc=None):
     """Send plain text message."""
     if isinstance(txt, unicode):
         msg = MIMEText(txt.encode('utf-8'), 'plain', 'UTF-8')
@@ -152,7 +152,7 @@ def send_mail_text(request, to, frm, subject, txt, cc=None, extra=None, toUser=N
         msg = MIMEText(txt)
     send_mail_mime(request, to, frm, subject, msg, cc, extra, toUser, bcc)
         
-def send_mail_mime(request, to, frm, subject, msg, cc=None, extra=None, toUser=None, bcc=None):
+def send_mail_mime(request, to, frm, subject, msg, cc=None, extra=None, toUser=False, bcc=None):
     """Send MIME message with content already filled in."""
     if isinstance(frm, tuple):
 	frm = formataddr(frm)