Commit to the Email Token or abandon it.
If you commit to the Email Token in the Subject line then any email without a token does not get tracked into CRM, without exception for any reason. Any email with a token in the Subject line gets tracked into CRM when received, without exception for any reason.
The situation is that emails are being tracked into CRM because at one point in time they were a tracked email and their 'Conversation Index' is hidden in CRM somewhere. When Server Side Synchronization detects a matching Conversation Index it puts the email into CRM, regardless of any other email synchronization setting. If I set token matching in Server Side Synchronization that is the only matching it should use, period.
The real problem is that there is no visual indicator to a User that the email they have been sent is being tracked in CRM, therefore they do not know their response is going to be tracked. If any sender at any point removes the token the email should no longer be tracked. If someone pastes a token in the Subject line the send of that email and all subsequent send/receives should be tracked so long as the token is present.
All emails without tokens should qualify for Email to Case processing and only be disqualified by the filters set in the process by the Administrator.
Not having a visual indicator in a message that it is being systematically tracked raises security and privacy issues especially with our EMEA Users. There is an expectation of privacy between the sender and the people addressed in the message. The recipient may choose to share the message with whomever they wish, but that is at their discretion. With CRM a message can be attached to records that are accessible by many levels of User regardless of who the message was addressed to and with conversation index matching the email goes into CRM without the knowledge of the sender.
Thanks,
Jim