My fault -- I wasn't clear because I didn't want to write an essay. I'm not talking about maps and secret doors. I'm talking about concealing the methods of resolving actions. I'm talking about the players being in the dark about how the DM is arriving at the results of the players' proposed actions.
When I first played D&D in the early '80s, my DM ran the game from behind the screen and I had NO CLUE how he was resolving in-game activity. And I didn't care. It was all concealed from me. I didn't know about to-hit matrices. I didn't know how he was deciding if I was sneaky enough to get passed the guards undetected. If he was making stuff up, fudging numbers, or rigorously adhering to dice rolls -- it didn't matter to me and I didn't care to know. In those days, my expectation was that almost all DM stuff was intended to be concealed. (I seem to remember admonishments in the game books that players should not even peruse the DMG.)
Now, more than 35 years later, I'm in a group with a first-time player who barely knows how their own character sheet works and has no interest or particuar expectation that the DM shares the methods of resolving actions. Is it dice? Is it making up stuff? Is it occassional fudging? This new player doesn't know and doesn't care. The DM is doing what DMs do by running the game.
And no trust is broken.
That's your expectation, and it's common, but it's not universal. Here's my version: the DM behind the screen is trusted to be the arbiter of in-game actions. That often involves dice. How much of the specific methods of arbitration are revealed to players differs from table to table. By all means, have the conversation about how you plan to run the game (or how you want the DM to run the game). If a DM tells you they're running a strict let-the-dice-fall-where-they-may campaign, the DM should abide by that. If they don't agree to that, it doesn't make them liars or show a lack of integrity.