Steve Losen writes ---
I can think of several common scenarios where a user ends up owning files outside their home directory.
[cut superuser scenarios] [cut mode 777 dir scenarios]
Another scenario that I've seen. If user B makes a hard link to a file owned by user A, in user B's directory, and then user A deletes his link to the file, then the file will continue to exist in user B's directory, owned by user A.
This happened a lot in my undergraduate college days, when we had really small quotas, and wanted to have lots of programs. One student would compile the program, and then lots of others would link to it, thereby avoiding the quota. Hard links were used instead of soft links, (or just setting the path) because when a user left the school, the admin's didn't go hunting the files down across the entire filesystem, they just removed the homedirs. There were files around that were owned by students that had left over 5 years earlier.