Normative Signs: The Poetry of "Ought"

This one is on a fence around a Toronto school. It says “Entry upon this school site for any purpose inconsistent with the Education Act is prohibited.”

Wow. I realize that ignorance of the law is no defence, but do they actually think anyone reading this sign is going to be familiar with the Education Act and its requirements? This is clearly what you get when you allow lawyers to make signs.

Addendum:
I guess from a normative point of view, the goal here is to make the sign emphatic, by pointing to legislation. And maybe, at some basic level, that could work. But I wonder if it actually informs behaviour, when so few people will know just what’s in the relevant legislation, and hence just what the sign is actually prohibiting.