Either: 1) So that there can be co-ordinated coverage of it in the media / social media, and it doesn't just become a thing that's "in the public domain" but i

Either: 1) So that there can be co-ordinated coverage of it in the media / social media, and it doesn't just become a thing that's "in the public domain" but isn't news; 2) Because it's FUD. Confidently declaring that things are going to happen on certain dates is a really powerful thing (cf. millenarianism) I don't know which it is in this case.