hawkeyefan
Legend
Forcing or purposefully rearranging stuff for a desired outcome after a choice has been made typically isn't my preference when it undermines player agency. I don't see much of a difference between fudging a DC or die roll or path that would have revealed a secret item versus forcing the issue to make sure they find the item another way.
That being said, if your players are cool with it, it's all good. Some people still love to watch the magic trick even when they understand the illusion. For others, it sours the experience and the magic (or trust) is gone.
I wouldn't always defend making such changes. I've seen the word "railroad" pop up in the thread....and I don't know that a GM making a change would always be railroading. Although it could be, there could also be other reasons. I think that per the OP, the decision is made to help keep the game moving, or to reward exploration, and so on. To help enhance the drama in play....not to force the pre-determined outcome.
Having played a few games where there are elements that are not determined until the dice are rolled, it's easy to understand why deciding such things on the fly doesn't need to limit agency.
The way I look at it, one of my roles as GM or DM is to keep the game moving, and to try and make it as interesting as possible. To me, that's far more important to the game experience than adhering to the exact text of an adventure.