You’ve assumed here that the default is for Alice not to share, while it might seem positive if the default was for her to share. So in practise, it’ll depend on how many new shares it incentivises (including people who only went to the effort to discover the information since blackmail is legal) vs. how many people benefit from being able to trade. In practise, I suspect the first factor will easily outweigh the second.
You’ve assumed here that the default is for Alice not to share, while it might seem positive if the default was for her to share. So in practise, it’ll depend on how many new shares it incentivises (including people who only went to the effort to discover the information since blackmail is legal) vs. how many people benefit from being able to trade. In practise, I suspect the first factor will easily outweigh the second.