Delivering Awareness

As all of the web developers out there me too have often to deal with graphic designers, photographers and other "creative" people. Most of them, for historical reasons, are Mac users. And I almost daily receive some compressed archive of mockups and assets, in which I regularly find the well-known __MACOSX folder. Well-known, but hardly understood or useful.
For the records, the __MACOSX folder seems to be a mixture of metadata, personal configurations, backups and whatever, never intended to leave the device that generated it. It is attached to all outgoing compressed archives due an architectural design failure, and it's just a waste of bits for the receiver of the archive.
That said, it inspired me a quite bizarre idea: if MacOSX users can waste my own bandwidth and disk space to deliver me binary files with no meaning, just for their own convenience (or to comunicate their proudness in being wealthy enough to spend double the money for a high-level laptop), why I cannot waste a few bits to deliver awareness about software freedom?
The method is exactly the same: inject a custom file into newly generated archives. Not some binary and unreadable file, but a plain text .freedom.txt containing hints about the argument and an invitation to dive deeper into the issue.
I've hacked a naive solution, wrapping the tar command in a Bash function saved in ~/.bashrc, and I've published it here. It is just a loosely proof-of-concept, it is limited to tar archives and to invokations from the command line, and cannot work in many situations (e.g. using the -C option). Eventually I will provide more coverage for other archiving commands, even if a better approach would be substitute the executables in /bin folder (to work even using graphical frontends, such as File Roller) or even hijack calls to the system libraries providing archiving and compression function.
Contributions and suggestions are welcome on the GitHub page.