Indirection in Drupal - How to dizzy the next guy

Drupal has gained some powerful tools in recent year(s). They are all valid and useful. When used improperly though, they can become dizzying. Consider these misdirections ....

• Rewrite arbitrary SQL queries fom your own module
• Rewrite forms from your own module. Add/remove fields and change the Action attribute
• Alias some system urls so he can't tell what module is handling the page
• Implement some theme() functions so he can't find who is outputting an HTML chunk
• Drop small node-story.tpl.php files in the theme directory so that he can't figure out why stories look different.
• Use menu.module to restructure your Navigation block. Change some link text while you are there.
• Use the 'arbitrary PHP' feature of blocks to show only for certain people on certain pages.
• Implement advanced database prefixing so that he looks at the wrong tables by accident. Ouch!
• Switch themes from some obscure part of your code by changing the global $custom_theme variable.