But all programs must make exceptions for these entries. Imagine trying to add a third magic filename, '...', for the grandparent for example. You would have a lot of coding to do. Not really possible. It would have been better to mark the dirs as special somehow rather than having each program have the convention programmed in.
...and of course even the kernel had to have exceptions for them anyway - it knew they were special because it had to stop userspace from unlink()ing or rename()ing them.
