Word matching in the subject line and body of the email to detect an out of office reply is unreliable.
Users creates a ticket
The ticket is worked and closed
An email is sent to the user about the ticket closing
The user sends an OOO reply
The out of office reply is ignored
The out of office reply creates a new ticket skewing our metrics
If the recipient email server is RFC3834 compliant a header field will be added "Auto-Submitted" where that field has any value other than "no". Allowing us to match on email headers would allow for more reliable filtering. We could eliminate the edge cases where users out of office reply does not contain the words we expect.
Parsing the email headers could be useful for other scenarios too. For example - Web forms could inject specific headers and would be filtered reliably.