About simply declaring "World Peace!" and just leaving the room? Yeah, that happened, and the Iran deal still had quite a lot of issues that reared their ugly heads later.
One key difference is the people at play here (I wouldn't trust anyone in the Trump administration to bag my fucking groceries, let alone negotiate peace), and the fact that the negotiations seem extremely rushed. At this time last year people were worried about nuclear war with NK, and now we've swung so hard the other way we're getting whiplash. My chief concern is half-assing a treaty because Moon and Trump want to score political points with their respective countries and set up issues in the long run in the future. Given this is Trump we're talking about, the onus is on him to show that he's not gonna fuck it up.
I would agree that Trump, and his supporters by extension (just look at the OP), and Moon are playing this pretty desperately. At the very least, we should get the Americans in NK custody released when we're giving them a propagandist's wet dream of a photo opportunity.