Anti Existing Field
Disable the option to re-use CCK fields (prevents splitting fields into separate tables when new fields are added to a content type). This is useful when custom modules have hard-coded SQL queries to CCK field tables where re-using a field would break the queries.
Current options are disable the submit button, remove the form, or prank the user to move the button around the screen on mouseover.
From what I've seen, Drupal 7 fully normalizes content type fields by default, therefore this module couldn't prevent it. Unless someone can demonstrate otherwise, there is no point in using this module in Drupal 7, even as a gag.