I don’t think it was anyone’s “idea”. Just that people are so busy and the world is moving so fast, the only time they see friends from the Parish is at Mass, and they are anxious to pass news and greetings before everyone leaves afterward, which leaves them only prior to Mass to greet each other. Greetings are fine, especially to pass news of a birth or death to friends they haven’t seen for a week or two – but the Entryway or Hallway near the entrance should be the place for this. In warmer weather, outside is even better. During the winter, it would be too difficult for all, especially children and elderly. Encourage the greetings/news near the entranceway. The Sanctuary is for prayer and preparation for the Holy Mass.
What my Priest did is not proper procedure, but he did get everyone to keep greetings out in the Hallway. However, this is not a proper Adoration, and shouldn’t really be used just to shut people up. That is not the purpose of Adoration or the Exposition of the Blessed Sacrament. A notice in the Bulletin each week, and perhaps a few weeks in the announcements will quiet things down and remind the adults that this isn’t the place for “getting together socially”. And move them outside the Sanctuary prior to and after Mass. If they want a “meet and greet”, a lot of churches I’ve visited have it in adjacent rooms used by the Parish AFTER Mass for hot coffee, hot cocoa (iced tea in summer) and some donuts or cookies donated by ladies of the Parish. Much more practical, and maintains the sanctity of the Sanctuary too.