Principles are ways of successfully dealing with reality to get what you want out of life.
Ray Dalio, one of the world’s most successful investors and entrepreneurs, cites principles as his key to success.
You just have to know what they are like and get a sampling. Regular sampling of a statistically reliable number of cases will show you what a person is like and what you can expect from them. Select which of their actions are critical enough to need preapproval and which can be examined later. But be sure to do the audit, because people will tend to give themselves too much slack or could cheat when they see that they're not being checked.