Mail top senders

[bear]

Can anyone tell me if mail sent from the default POP account to another POP account on the same domain counts towards the "Top 50 local senders by message count" stats in WHM?

I have a few accounts that are set up to discard mail to the default POP (using :blackhole: ). Aliases I want mail from go to a secondary POP account on the same domain. The mail is first seen by Spamassassin, and then the ones that aren't discarded are flagged and then filtered by the secondary POP account filters.
This has been working quite well, but I've seen in the stats that these accounts are "sending" quite a few messages that haven't originated from me specifically, and I'd like to rule out someone abusing the system.

Anyone know, or perhaps know of a method to verify where these messages are being "sent" from?

[bear]

So...it's either a really dumb question, or it's really difficult and no ones has any idea.
No takers?