It seems to me that false apparitions always lead to establishing de facto ghettos of 'believers' or at the least the false apparitions lead to an 'us and them' mentality completely at odds with the Commission of Jesus to go into all the world, preach, baptize and teach. Real apparitions produce all sorts of enduring fruit .
Our Lady of Knock, Queen of Ireland, pray for us.
Yes, and that is probably the way I personally discern my belief or not, in the apparition or revelation of the visionary. Plus, I generally have always gotten "an uneasy" feeling about some of these "visions" when I study up on them. Hard to describe, but very real to me.
I've been to Knock! It was wonderful, but I was sort of underwhelmed by the modern architecture - but most of the Catholic Churches in Ireland are the same (thanx, Henry VIII).