Upthread I shared a recent experience where we were all roleplaying, and one character made such a logical argument the NPC just went with it, and it wasn't until later the DM realized it. While it's all well and good to say "no automatic success", are all the players and the DM on the ball enough to go "wait, point of order, persuasion check?" if something like this occurs?
Well, from my 30+years of roleplaying, I honestly don’t recall it ever happening.
But hypothetically, if it were to happen, I don’t think it would be a real problem. DnD is not a competition and nobody is perfect, so honest mistake can happen. First of all, if a situation that could have necessitate a roll would pass under the radar, you should start by asking yourself if a roll was really necessary. If everybody missed the window, could be that a roll was not important in the sense that it would not have change much regardless of the result.
Then, if it was really important and somehow we would have all missed it, there would be two options. Either me as a DM accept that I made an error and move on, or we all discuss it and try to find the best solution together that benefit the story.
As a GM, one of my first personal rule is to not punish the players for my mistakes. So just like in a combat if I forgot to roll for additional damage a round or two ago, I won’t suddenly roll it to damage the player, I will accept my mistake and move on. So if I forgot to ask for a roll in a social challenge because we somehow all missed it, I won’t suddenly go back and reverse the call. I’ll roll with it. Mistakes happen, the important thing is that nobody feel cheated.
It might help that I don’t play with strangers, only with friends, or people that a friend vouch for. And we are all approaching the game as a cooperative game, not competitive. As a DM, I don’t play against my players, and players don’t see me as their opponent. We’re all in this to try to have the best experience as possible.