The 'Insert Note into Clean Message' option is greatly depreciated in that it is easy to fake and these fake 'email scanned by XXXX (insert AV of choice) and found to be clean have been used in malicious emails in the past and who trusts that anyway, I certainly don't.
Why is it needed when if an inbound email is infected avast will alert, brand the email Subject and remove any infected attachment, etc. For outbound email it too would alert if infected/suspicious, etc. the only real benefit is promotion of avast. Who trusts it if the message is from other AVs, so why would they trust it is from avast!.
It really doesn't bring any additional in the way of security, potentially the reverse as opening an email could actually initiate a remote attack. So looking inside an email for a clean note could potentially put you at more risk, it certainly isn't something I would rely on.
As an avast user (who previously used the outbound clean note to promote avast) I believe that the above comments are why avast! took the decision to end this option. Not to mention that in some email clients (Incredimail I believe) this option wasn't completely compatible.
For me the thought of going backwards to an older version of avast with a lessor degree of protection or switching AV, for something which provides zero extra protection for what are cosmetic reasons, is not good.
