Some things in policies can be good controls, but the same controls can open up vulnerabilities or can be contradicted by other controls and conditions in other policies.
What can be a good measure to prevent this?
Example: I say to my employees that no-one has the ability to access room FR1 after 7pm on Wednesday, but in the same policy I also alerted employees that everyone who can confirm a valid authorization are allowed in room FR1 until they leave, no matter what time.
This is just an example, but in reality, it is much broader than that. To be 100% clear, rules that interfere with other rules and that combination will fail because of confusion. I want to prevent these kinds of complications.