Postini being too informative?

[#1]

For years I have used a mail redirector elsewhere where my domain is hosted to route my main mail to one of my Plusnet mailboxes, which is never disclosed ...
... apart from by Postini, it would now appear.
Is it necessary when Postini rejects spam for it to disclose the address which has refused the spam?  It's almost as good as suggesting that it exists.  I discover this because of the commonplace ruse of the spammer spoofing the mail to have come from my public email, as well as being sent to it.
But I would have thought that if the spam filter is going to reject it, it ought to do just that, and be as unhelpful to the spammer as possible.

[#2]

I'm not sure this a Postini specific thing.
Your redirector service will be sending the message via Postini no differently to that of the redirector sending it elsewhere. This means this information would be available regardless of who bounced it.
It's often down to the reason for the bounce if the address is displayed. It is however displayed in near enough every occasion.
You might not be aware, but we are due to move away from Postini.
http://community.plus.net/blog/2008/11/04/ironport_technical/

[#3]

Quote from: P

You might not be aware, but we are due to move away from Postini.

Thanks for posting that link.
Well, at least it means I will eventually be able to retire the filters I'm having to use to get rid of the copious Postini headers reporting as spam mails with a spam score of 0.0!
The IronPorts should be good news. Just as long as they aren't set to bounce everything inbound which fails a reverse DNS on any server through which the mail has travelled.