I saw The Usual Suspects not only knowing there was a twist, but basically being unable to avoid the twist (it being an old, famous movie and me having TV Tropes). I didn’t know all the details, but I knew the gist of it. I still thought it was masterful, just the framing of the story and the smooths transition Kint makes from cripple to badass in the last shot is nothing short of wonderful. While the twist plays a big part, I certainly don’t think that the filmmaking is in any way marred by knowing the twist (YMMV and all that).
Still though, you’re always going to get that on dedicated boards to anything. Even sites that basically have the spoiler police allow thread titles like that. Otherwise the board becomes a pain to read, or you have to open the thread to figure out what it’s about anyway, spoiling it more. It’s annoying when on GameFAQs you get a thread like
“How did you feel when… (spoilers)”
and then the first line is “the Commando exploded.”
Sure you get a spoiler warning, but when you’re dealing with a 40±hour long medium like a game, or even a TV series you basically have to avoid any discussion of it until you’re caught up if you want to remain a COMPLETE spoiler virgin, and I don’t think I can claim it’s common decency to avoid that flaw. I think it moves too far in the other direction of topic censorship to claim dedicated boards should avoid any discussion to accommodate any possible person who waltzes in.