The Video Guy offers opinion re: movie spoilers, for what it's worth:
There should NEVER be a statute of limitations; there should NEVER be a point beyond which it's okay to divluge critical info regarding a plot. No one should EVER, for instance, talk about the ending of Sixth Sense. There is absolutely no excuse for it and no reason for it. There will always be someone who hasn’t seen a particular film, so what’s so important about what someone is communicating that s/he has to reveal critical info from a film? I say: STOP IT! There's never an excuse to relate info that might ruin a movie for someone else...ever! Period!