email_to_user() sends emails even if email processor is disabled

There are still a few places in Moodle which call email_to_user() directly rather than going through the messaging system (for example forum email digests).

A client of ours has noticed that while email_to_user() makes use of email processor configuration settings such as $CFG->smtphosts, it continues to send messages even if the email processor is disabled.

I take their point that this is not entirely consistent behaviour.

Would this be considered a bug?