I'd like this scenario: All unregistered users get the CAPTCHA on edit, registered users only get it if they add a URL, and autoconfirmed users never get it.
This could be a popular setup, but unfortunately it's not possible with the current customization options. My recommendation for how to fix this is to have it work just like user rights:
$wgCaptchaTriggers['*']['edit'] = true; $wgCaptchaTriggers['user']['edit'] = false; $wgCaptchaTriggers['user']['addurl'] = true; $wgCaptchaTriggers['autoconfirmed']['addurl'] = false;
I think this makes a lot more sense than the binary skip/no-skip approach, and it would allow people to customize ConfirmEdit however they want. I've submitted a bug/enhancement for this as well.