Bb 2016 Theme (Ultra Theme) causes major changes in how search engines (Yahoo, Bing, less so Google) rank your Blackboard environments. We've run our staging system for along time and never had an issue with it popping in search results. After putting the new theme in staging, the search engines must be ranking responsive design sites higher, because it started to show up above the production site in Bing and Yahoo. We are working with robots.txt and site ownership files for Yahoo and Bing, but this may be something to think about during the upgrade season.
The end result is that we had at least one student login to staging and complete homework there .