Yes, this is a feature of the Anti-Virus software we use.
Whenever you see {disarmed} it means that a web bug or tracking code was found in an e-mail and our ANTIVIRUS software removed it.
That is to say, a code was added in the email that would sent information back to a remote server without your knowledge or consent.
These are most often found in HTML e-mails and SPAM to track when users open and read their e-mails. The {disarmed} tag means that the the tracking code was removed but other than that the e-mail is unchanged and will look normal.
You will not see this Status if the email is clean.