A costumer yesterday ask the exact question i found on this link http://www-01.ibm.com/support/docview.wss?uid=swg1LO43023
If a DWA message disclaimer is set and a DWA user sends an email where the recipient is an internal user – i.e. address is Notes mail format not internet format, the Notes user receives the message disclaimer.
This is a known behavior in Notes/Domino and reported to Quality engineering in SPR # KBRT67FN7B as an Enhancement request and currently there are no plans to address it in R8 and R8.5
