A policy and law are different from each other and are enforced in different ways.
When a company has a policy it's just a rule they have in place where you should comply and must comply with to be able to enter the business or work with the business.
If you do not follow the policy of the company or place then you cannot be at the business or deal with the company.
For example if you go into a business and they state that by their policy you must not wear a hat and you go into the business wearing a hat then they can ask you to leave and you must leave or take your hat off.
Now they cannot force the police to force you to remove your hat to be in the business since it's not law.
But the police can be called and have you trespassed from the place.
Now as to a law that is where you can get into trouble for breaking the law.
If it says that it's against the law to wear your hat in someplace then you could be arrested for going into the place with your hat on.
That is unlikely though but just an example.
A law the police can enforce but a policy of a business the police cannot enforce.
That is unless you're at a place such as a courthouse where there policy is you cannot take your camera or wear your hat in and then you must comply with the policy or be escorted out of the building.
However you won't be arrested unless you go back into the courthouse with the camera.