This actually happened during my last game.
I was The Keeper and one Investigator was playing Gloria, she used her once per game action, which I transcribe here:
"Action: Once per game, look at all Exploration cards in the room of your choice (you must then return them in the same order)."
She choses the exactly room where the Clue 1 was, the one that reveals the Objective.
The Investigators all claimed me to revel the Objective, and I thought that that was the wrong mechanics.
Card's texts only triggers theirs abilities when "investigated" by a Investigator.
Since the "look at" ability does not means "investigates".
Since the Clue was looked at, it was revealed. And revealing the clue (in this case) meant reveal the Objective.
My opinion is that Situation 1 is the correct one, since revealing the main Clue without having to get all keys and solve all the required puzzles can potently break the game.
But since Gloria's ability is a once per game, random room situation. Having the final Clue revealed this way is a lucky shot. And should be treated as a "epic" move since revealing the objective without having to pass thru all the required steps (keys and puzzles).
I have searched the rules and did not find anything that could make Gloria's ability clearer. It seams to me that's a matter of what the game's creator had in mind when creating this mechanic.
Hope I made my point clear,
The Wing Warrior - learn more at www.facebook.com/thelegendriders
Getting to sneak a look at the clue isn't the same as acquiring the clue. When you explore, you take the cards and place them in your character's play area. This is the point when you would activate any clue text - if the card is looked at and then replaced on the board, you have not acquired the clue and therefore cannot reveal the game objective.
You have to treat this like a psychic vision: Just because you have seen where the clue is, doesn't mean you have found the clue or know what will happen as a result of finding that clue.
Remember: If you played this ability that it allowed you to claim the last clue, you could theoretically reveal the final clue on the first turn of the game, which would definitely break the game.
That being said, Psychic Sensitivity is still pretty broken. Anyone with prior knowledge of objectives can figure out which objective when they see the clue, even without revealing it.