Exchange 2010 SP1: MRM : DPT Applied on email items do not TAG email Items

Recently I was asked a question on MRM. when you apply a single DPT on entire mailbox

email items won’t get tagged. but DPT is action is applied on email items.  is this expected behavior ?

If you have one Retention Tag created  for the Entire mailbox to “move items to Archive” or   

“Delete and allow recovery”.

- Apply the tag to user mailbox via Retention policy

- When MRM processes mailbox, email items get processed according to retention period set on  DPT. but emails will not be tagged with any retention policy.

Q. should we see email items being tagged ?

Ideally Many customers want users to know the policy being applied on their mailboxes. But email items will not be tagged if you have one DPT applied on user mailboxes. THis is Expected behavior in Exchange 2010 MRM Infrastructure.