We'll be able to tell how many people did it by how Facebook reacts. If they do basically nothing and carry on as normal, then we know that FB knows that hardly

We'll be able to tell how many people did it by how Facebook reacts. If they do basically nothing and carry on as normal, then we know that FB knows that hardly anyone has deleted their accounts. If it looks like FB is shitting bricks, then we know they're hella scared, which means enough people deleted it to scare them.