> Without case law, authorities don't know neither.
Authorities are the ones who create the rules. If they tell you what the rule means, that's what the rule means, because it's their rule. That's the point of having them be the one to tell you.
You can write rules without knowing how they'll be broken.
Some people defend themselves by saying they didn't take the action they're accused of, others can cop to the action they took, and argue that the law doesn't apply because x, y, z.
So, like, that's why case law is a whole thing, it extends "the rules" to "here's how the rules have been interpreted in these situations"
Authorities are the ones who create the rules. If they tell you what the rule means, that's what the rule means, because it's their rule. That's the point of having them be the one to tell you.