Back up one step further: what evidence do we have that the Interdict actually exists? As opposed to, say, all powerful wizards simply having the same inclination toward secrecy and self-discovery. How did Quirrell put it...

The fools who can't resist meddling are killed by the lesser perils early on, and the survivors all know that there are secrets you do not share with anyone who lacks the intelligence and the discipline to discover them for themselves! Every powerful wizard knows that!

I've never received the impression that wizards powerful enough to be subject to the Interdict have actually tried to circumvent it. If all known examples of written instructions for powerful spells were gibberish to begin with, would the world look any different? Not to mention, why would it be necessary to cast a huge mind-altering spell to make people do what they were inclined to do anyway?