OOXML validating mailfiler

I take strolls with my roommate, Håvard, quite often. Today, we touched on the subject of ODF vs OOXML after a longer discussion of document validation in general. That's when we hit upon the idea of the OOXML-validating mailfilter.

The idea is quite simple: In addition to your anti-virus, spamfilter, greylisting, and other filtering functionality you have on your mailserver, you add a small script which relies on unzip and xsltproc to validate any OOXML document that passes your way, and automatically rejects any non-conforming document with a stern warning, such as:

It appears that the document <file name>, created with
<document producing program>, is corrupted. I will not be able to
read this document properly. Please consider resending a conforming
OOXML document, or use a different document format, such as ODF.

Pedantically yours,

<your name>