@REP
What headache?
Put simply, some people believe that ideas have value and will go after an author in court if they think that their idea was used in published material. Said case will lose, obviously, since copywrite only protects the unique expression of an idea in media, not the idea itself, but you still have to defend yourself which can be a long, stressful, and expensive process.
This has been an issue for a long time. J. Michael Straczynski, creator of Babylon 5, was personally active in the show's usenet group back in 1995, but he asked mods to enforce a policy of nuking any post that included suggestions for future episodes. Wild speculation was fine, but he didn't want to deal with angry fans claiming that some future episode having idea A instead of idea B was because of fan popularity or something.
Terry Pratchett had a similar policy that was even more rigorously adhered to when he was on usenet. In his case it was even more of an issue because unlike JMS he didn't outline future books.