Just an idea if you wanted to investigate it further. RAR supports adding a recovery record so that even if the archive is damaged you can still recover it. I've used that feature on more than one file.

Yeah, many of the installation don't use the Registry and some Admins manually install it so that could be a bit more problematic detecting and determining where it is. If you do want to go further with it though I can probably help do some of the research on it.