Super user does use permissions but then will allow override if directly specified
Not true... it does not do a permission check... observe:

Code:
[root@luna doc_root]# uname -a 
Linux luna.xxxxxx.xxx 2.2.16-22 #1 Tue Aug 22 16:49:06 EDT 2000 i686 unknown

[root@luna doc_root]# ls -l test
-rwx------    1 apache   apache          2 Dec  4 10:54 test

[root@luna doc_root]# vi test
*** change the contents of test from "1234" to "23456" ***
*** No errors or warnings are issued ***

[root@luna doc_root]# ls -l test
-rwx------    1 apache   apache          3 Dec  4 10:57 test
Root is able to alter files which it has no specified rights to, since UNIX uses a default deny model... clearly no check has been done.

Is this a real world example?
Yes, one of the operators at more former employer had rights like this... useful for deleting files that other users were not allowed to delete regarding various aspects of application development, etc (when they deleted these files they went to this directory) the operator would create new subdirs for different projects or points of deletion.

cheers,

catch