One of the things that was put in a recent 5.x release (I don't know the first one) was the automatic keeping of emails sent where the email address in the user table matches the to/from email address in a mail sent through the SendMail API.

So far I can't find a way to switch this feature off.  Is there such a thing?

The problem I have is that I have written modules to email administrators of certain actions the user takes.  For reasons of workflow, these emails are sent with the email address of the person in the 'from' field.  This makes it easier to file and organise the emails, but also allows the use of the 'reply' button if the person needs to be contacted.  Because of the new messaging design, I've found out that, when the email address matches one on the user table, the email is not only saved in the Messaging_Message table, but the person in the 'from' field appears to be getting a copy of the email forwarded to them as well.  In many cases, this is unwanted and unnecessary, but I can't find a way to switch this functionality off?  I understand this is in place for future operations, but can we get an 'opt out' either for certain messages or for all messages?

Sebastian - that's possible, but I'd rather a portal level switch to turn the messaging retention on or off.  A lot of sites won't need it and it just adds storage, processing, etc.  Even better would be the ability to opt-out via an overloaded SendMail API call - default retain unless a boolean value is passed to say 'don't retain this message'.