I have about 50 different Prefixes and wondering if the wording of the Prefixes is being indexed by Search-Engines? The Prefixes actually do have an ID, but not the name itself included... so I am not sure if Prefix-words are indexed ?
That should hide prefixes from page titles inside of threads. But search engines usually don't like it when you change the content just for them. It's called cloaking. This is a minor change, but it's something to be aware of.