Well, there are some "black holes", such as the calendar, where they can go up day by day into oblivion, but that's an easy fix with robots.txt:
User-agent: *
Disallow: /forum/ubbthreads.php?ubb=calendar
Disallow: /forum/ubbthreads.php/ubb/calendar
Disallow: /forum/ubbthreads.php?ubb=showday
Disallow: /forum/ubbthreads.php/ubb/showday

I am a Web Development Contractor, I do not work for UBBCentral. I have provided free User to User Support since the beginning of these support forums.
Do you need Forum Install or Upgrade Services?
Forums: A Gardeners Forum
UBB.threads: UBBWiki, UBB Styles, UBB.Sitemaps
Longtime Supporter & Resident Post-A-Holic
VNC Web Services: Code Modifications, Upgrades, Styling, Coding Services, Disaster Recovery, and more!