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Frankly speaking there is no reason for you to keep the Security Function switch ON. I have around 20 websites done on Joomla CMS and all of them packed with sh404SEF since I found it the most accurate and bug free SEF component for Joomla.  And during all this time I have been using it, the Security Function has been Switched OFF. Same I will recommend for you, it is useless. And remember the main purpose of sh404 is to make your website more SEO friendly but not to prevent from hacker attacks. So it's not an security component so far and still it might have a lot of bugs and mistakes. BTW I read somewhere in INTERNET that many people had the same problem like you, but with different robots, not only SEOmoz. So you should be also careful because it might make a negative impact on other search engines. I advise: Turn this sh*t OFF ;)))