Forget about the intent.
No, that's out of the question.
This rule is
specifically about intent, as much as some people would like to make all the rules simple cut-and-dried, "Did this happen? Was it in a situation that was absolutely clearly that? Then punish!"
If that's all there is to it (Secession? Check! Friendly with parent realm? Check! During war? Check! Close to the border with the realm they're at war with? Check!), then we don't need Magistrates. All we need is a relatively simple algorithm to recognize 3 of those 4 criteria and post an alert, and a couple of humans receiving the alert to do the fairly simple check of "are they friendly with the parent realm?" and if so, press the "yes, punish them!" button.
But the Magistrates are supposed to actually
examine evidence and
make judgments, not just hide behind "I don't want to try judging intent, because people are hard to understand, and some of them will try to trick you!"
If that's just too hard, then what the hell is the point of having human Magistrates anyway?