Hi Vince,
I understood you. The only thing I did not realize is that the Thank you message said "Thank You! Your message has been sent." I am changing that to say "Thank You! Your message has been received." so that it does not imply that an email has been sent but only implies that the form submission has been received. I guess that message made you think it was an error but it was not. The Contact Form can work fine even without an email address, so the user who submits the form need not be concerned about whether notification is enabled or not.
If the email notification address is left blank the contact form does not try to send an email, but it still says thank you because it captured the form submission.
I will add an INFO level logging so that if the notification address is not configured it will log this:
"contact form submission received but not sending email because notification email address is not configured."
Best,
Joe