Hypothetical: Let's say a player has declared that their character is looking for something in particular and describes their method. A second player declares that their character is assisting the first character and describes how. The first character is trained in Perception and has the Observant feat, making their Passive Perception 10 (Base) + 5 (Observant) + 5 (Advantage) + X (Attribute mod) + Y (Prof bonus) = 20 + X + Y. It is thus impossible for the character to roll higher than their Passive Perception. As a DM, in such a circumstance would you ever tell the player of the first character to roll an [Attribute] (Perception) check? Or would you rely solely on the Passive Perception to resolve uncertainty (if any)?