Since I'm too lazy, do this: use the preview function to find a combination of tags that work as spoiler tags, then post. I'd do it if I knew how, but I just don't know how.
Or you could use Firefox for Head-Case, and IE7 for everything else, nothing says that you have to use one browser for everything -- I have Opera installed for exactly one site.
Oh, and your other problem about being exposed to spoilers -- welcome to me, circa 2007. How do you think I became the spoilers nazi?