AITJ for hiding the fact something could be fatal
I (elderly male) was in charge of a extremely powerful and dangerous item and it's nullification device(unfortunately that was lost long ago) but I did know everything about both of them.
One day the device was stolen by a totalitarian ruler and I sent out most of the information I had on the nullifying device to the public but leaving out a one detail so people would look for it
Fortunately someone did find it, unfortunately he was bound to it so that one very critical detail would be fatal. I didn't tell him this until we were preparing to go stop the dangerous relic.
We are currently on our way to break in to the ruler's headquarters now, AITJ.