I see this suggested from time to time - from [MENTION=463]S'mon[/MENTION] upthread, I think, and it was mentioned in another thread that I read recently - but I'm not a big fan.D&D gives you a decent way to deal with this: Intelligence, Wisdom, and relevant skill checks. If the plan is smart, let it lie. If the plan is bad, and the PCs should have all the information, but the players have missed something, run it through the dice. If they dice say no, you let it lie.
If the game would play better if the GM speaks to the players, then speak! If there's no obvious need to speak, then don't! But I don't see the point of leaving it up to the dice in this sort of situation.
(The sort of situation where I might use an INT check is like one that came up in my game recently - the PC encounters a signalling system s/he has never encountered before, and tries to quickly decipher it. But that is not about the foolishness or otherwise of player decision-making - it's just another exploration mechanic.)
This is an ideal which unfortunately is not always reached. The best notetakers in my group both now live in England, and the quality of notetaking has declined among those of the players who remain. (We play on Sunday afternoons, often still tired from work, and with kids playing in the background. Both internal and external factors make good note taking harder than it used to be.)Players should be actively participating and writing information down. So the chances of missed or forgotten information is kept to a minimum.
The frequent turnover of PC sheets in 4e is also the enemy of good notetaking, as notes on old PC sheets get lost in the updating.
So I'm reasonably forgiving in this department, and generally happy to help my players out with their PCs' memories - this generally comes up because they remember that they should know something, but can't remember what exactly it is. If they ask me, I'll tell them.
This does sometimes reduce the dramatic force of a revelation, if the players don't fully feel the force of the big reveal on their own. But the alternative is just ignorance about the stakes of the game, and that is worse for drama, and for play generally.