http://en.wikipedia.org/wiki/Our_Lady_of_Kibeho
Speaking of predictions that were spot-on ...
That’s not the key point, of course. St. Catherine Laboure made a number of predictions, of which some turned out correct, and some totally wrong. About the latter, she just said, “Yes, I was wrong.”
Remember sometimes in history like Jonah with Nineveh warning which was destruction from the Lord. The city repented and the Lord did not destroy. I think of these old testament stories when the apparitions occur. I do not know about this St Catherine Laboure though. I have not read much. But a prophet that predicts and it does not happen is not a prophet as the bible defines. Also I guess an exeception to the rule because of God’s compassion.