If people are stupid enough to go into a discussion thread specifically about that movie once it's been released then that's on them. No need to change thread titles if people are that stupid they'll go in anyway.
It’s not even going in the threads either. If you’ve ever used Tapatalk the latest post is already in your feed without even needing to open the thread, but if you use a spoiler tag, Tapatalk replaces the post with a monkey holding his mouth. Just be courteous for a week or two for your fellow posters that haven’t seen it yet.