Would it be so hard to just say you’re about to mention spoilers and then talk about whatever you want? It’s just a common courtesy that takes no effort. We even have spoiler tags if you want to go the extra mile but that’s not even necessary. Just say “Spoilers for Example Property ahead” or something like that and then that’s it. You can talk about what you want and still be courteous to people who haven’t had the same media exposure as you.