A chapter heading that promises an arrest at dinner has already done quite a lot for me. Nobody has even sat down, and I’m willing to read several pages of people being aggressively polite.
I like this sort of advance warning. A guest choosing a seat near the door, a host insisting everyone stay for dessert: those could be completely innocent details. With an arrest announced, I’d be reading them suspiciously. I’d still want to know who gets arrested, but I’d also be interested in how long everyone can keep pretending it’s a nice dinner.
A back-cover description that gives away a surprise the book is saving annoys me. I’m only trying to decide whether to read the thing. But a chapter heading is part of the story’s timing. The writer is choosing to tell me now, and I’m happy to go with it.
Once that heading has told me, though, I want the narrator to get on with dinner. Four more pages hinting that something dreadful is coming would try my patience. Yes, the arrest. We’ve established the arrest. Let them argue about the potatoes.