Version 1.25 provides a facility for automatic z-index discovery! This should ease the pain of chasing down the z-index for elements on your pages.
At first however I had my doubts that the extension was really doing something because one bot succeeded in even bypassing the extra captcha protection in all the forms. But the IP in question was not listed by projecthoneypot (nor stopforumspam), so the plugin simply could not function.
Thanks a lot for this extension, I recommend it.