I once used a concept that is essentially Matt W’s example. The game contained some shelves, which, at first glance, held only a bunch of non-descript stuff. Examining them didn’t tell you anything additional, but if you searched them it made a specific object appear. One play-testing comment that I got was that this made the item too easy to miss, because “search,” as distinct from “examine,” is not likely to be something that players try as a matter of course.
In the early days, my recollection is that “searching” was something that you might not try on every object, but if you ran into a roadblock and started going back to see what you might have missed, searching was one of the things that you would definitely try. (I have a very vague recollection that one of the early locations in Adventure – or maybe it was Zork? – required you to search a bunch of leaves in order to find something under them; examining the leaves did not do the trick.) These days, I guess that approach is somewhat out of fashion, but personally I don’t have trouble with the idea that a player might find himself stuck and have to go back over territory already covered, including searching, in an effort to find something that might not have been discovered the first time (although it could have been discovered if the player had thought of it). In fairness to the play-tester who gave me the comment, the particular item in my game was not one whose absence would cause the kind of roadblock that might cause the player to start searching things, even under the “old” approach.
Robert Rothman