User:SOTO/Forum Archive/Help!/@comment-32744161-20181012183405/@comment-24894325-20181013061512

I think a distinction is to be made between a self-made speculation and a popular well-established fan theory. The latter can be acknowledged with appropriate sources in the BTS section. A good example here is The Woman (The End of Time). It is widely speculated whether she is the Doctor’s mother. The BTS Portion documents all the available evidence for and against, including the script, statements by the creator, casting notes, etc. In other words, we are not documenting the speculation itself. We are documenting the reaction of the production team to this speculation. (Another example here is Face of Boe.)

On the contrary, an idea that just came to one's head yesterday is, to be honest, fanfic (or the beginnings thereof). So it is mostly disallowed. In addition to what have been said before, it can be flaunted in Discussions (provided it's a theory and not a fully formed story).