The always-thoughtful John Kim (who I interviewed for TT) has this to say about informed player decisions:

In general, I would say that if the player can’t make informed decisions about what game actions she needs to take to accomplish what she wants, then resolution is at the wrong level. Either the player needs to be given more information such that she can make informed decisions, or the resolution should be done at a higher scale [emphasis mine].

He goes on to give an example:

For example, if the players don’t have enough information to determine what they should do to find the sewer entrance, then I might simply have them make a single roll (say, Gather Information in D20) to find it. If I don’t want it to be a single roll, then I have to provide them with enough information to make informed decisions.

Man, but that’s a good way of putting it. (The whole post is here: Player Knowledge, Planning, and Intent.)