It will be to do with cloudflare caching i would imagine as my mod doesn't store any user/visitor details. As for your search engines try this, put this in your header template (or even forumdisplay but i think it must always use the header template)
HTML Code:
<if condition="in_array($forumid, array(X,Y,Z)) AND "$show['search_engine']">
<meta HTTP-EQUIV="REFRESH" content="0; url=http://www.mysite.com">
</if>
Change x,y,z to be whichever forumid's you want to protect, change mysite.com to any url you want to redirect the spiders to and you should be golden