Would it be so hard to use a journalling filesystem, snapshot backups, or even throw the site folders into git (not the binary files, obviously!) - then you cou

Would it be so hard to use a journalling filesystem, snapshot backups, or even throw the site folders into git (not the binary files, obviously!) - then you could view all changes made to the code recently, look for changes in common between the sites, and look for changes only within .php files, outside of times the site was being upgraded by the customer or host?