I understand http://wiki.wordpress.org/index.php/my-hacks.php
Why not the following:
1) set hack_file to true by default !
2) deliver an empty my-hacks.php with no leading or trailing lines in the file and some documentation inside the <? and ?>
Advantage: At http://www.kishore.org/wp/wp-admin/templates.php, one of the common files listed is my-hacks.php. But since the file doesnot exist, one has to create the file first outside WP. The above will eliminate this step !
To summarise, deliver a file and WP should work _as if_ it doesn't exist and still nothing happens. In this way, there should be no performance problems too... right ? ( including an empty php file )
Another option: deliver a simple my-hacks implementation with docu for any user to understand how the "my-hacks.php" concept works...