Is it a matter of "trust" or a matter of misaligned interests & incentives? Person A approves Person B's manuscript/grant/etc. They do it because it's good for

Is it a matter of "trust" or a matter of misaligned interests & incentives? Person A approves Person B's manuscript/grant/etc. They do it because it's good for them and their careers, not because it's "good for science" (whatever that means nowadays).