One thing that strikes you, looking at the sequence of apparitions in the last two centuries, is the fact that the protagonists are very humble people. Our Lady seems to choose those that, according to human opinion, would be less suitable both because they are "simple" and because of their low socioeconomic status. There's no doubt that She has adopted a consistent approach in choosing the small and humble, and perhaps due to the fact that the real sin of the world is the puffed up heart of men that reject God and want to replace Him. As pointed out by St. Paul, God chose what in the world is foolish to confound the wise, chose what in the world is weak to shame the strong, has chosen what in the world is low and despised, what is nothing to reduce to nothing things that are, because no man may boast before God (1 Corinthians 1, 27-29). Therefore fall within the evangelical approach that the things of God are realized through humility. Our Lady also chooses the smaller and simpler because they, as messengers of heaven, are more credible and, even from the perspective of men, they are not able to deceive. We know the weight of the cross that the children of La Salette, Lourdes, Fatima, to those of Medjugorje have born: eventually the local authorities themselves have been forced to change their mind, realizing that the children were not able to invent anything, nor could they implement intrigues that only adults would be capable of.