The UK premiere of Fifty Words by Michael Weller at Bath's Ustinov Studio ~ an excellent production incidentally ~ is pitched in the brochure as a study in male/female relationships: This is the night when they say everything there is to say, reveal every dark secret which has been kept hidden and reach new heights of passion and intimacy.
I'm not sure the cliché 'reach new heights' is apt for the tigerish wounding process but my point is, this is an effective taste of the content of the play, and dark secrets in marriage are usually to do with infidelity. You'd expect, wouldn't you, a cupboard full of skeletons and most of them lascivious. Within the play programme there's an in-depth analysis, by a relationship counsellor, of the role of affairs in marital breakdown. Adam seems to be seeking someone to meet his needs outside the marriage without entering into the depths of a committed relationship, Julia Cole explains helpfully. Again leaving aside the spacial metaphor (though depths seems to me profoundly more appropriate than heights for issues of cohabitation) this provides a not-surprising extension of anticipation for the viewer, yet the article is bannered in red

SPOILER ALERT You may prefer to read this after the show, it reveals various significant details or material that may spoil your enjoyment of the unfolding action.

This intrigues me.  Reveals plot detail, possibly. Preempts the pace of story-line development, maybe. But spoils your enjoyment? When did you ever say to anyone 'I don't need to see that new production of King Lear, he dies in the end you know.' Or 'If you haven't seen Three Sisters yet, don't let anyone tell you whether they get to Moscow or not because that would spoil it completely.'?  I don't know about you but if I like a play, or a film, or a book, I return to it with increased enjoyment, not in spite of knowing what happens but because of that. No longer a who-dunnit, but a how-and-why dunnit, in crime terms. It's only pot-boilers like The Archers (I imagine, I'm not a follower so I'm guessing here) that people feel aren't worth spending any time with once they know.

And maybe informed anticipation has a place even with sagas and soaps. Coronation Street website has SPOILERS on their banner, giving fans a chance to glimpse developing storylines. This is in line with Victorian melodrama, when punters couldn't get enough spoilers and storylines like Murder at the Red Barn were ripped straight from the newspapers. Nowadays we like a little more psychological subtlety but doesn't that make the facts of the story less, not more, important?

So I dunno. Would you watch an Agatha Christie's Marple on TV if you knew that story?  Will you make a trip to the cinema to see The Great Gatsby, or any other film-of-the-book for that matter?  Surely with live performance as with films we go not for the plot but the adaptation, to see what nuances and insight the director and actors have brought to the writer's words. And that's no disrespect to the playwright, it's the challenge and the delight of working in theatre.