When I worked at Sun Microsystems, they had a clever launcher shell script dealie for things like StarOffice documents that did usage tracking, portability fixes (usually setting obscure environment vars), and of course downloading and opening the actual document. Then they started sending those shell scripts as email attachments. One day they sent out an email telling people to not open executable email attachments: the full memo was a SO document wrapped in one of these scripts.

To their credit, after the inevitable replies to that email they never used that wrapper again (they moved the launchers to the centralized NFS install where they always should have been)