Yes and that is something which needs to be included in the list.
Though you could try and misuse the report false alert on a website, by reporting in the text input 'Your Message' window that it is a malicious site which isn't detected by either the network or web shields.
I tend to send an email to the usual virus (at) avast (dot) com address, with 'Undetected Malware - Network Shield' in the subject and details in the email body, no need for a sample.