They are not supposed to announce a DFing on Sunday. The reasoning (theirs) is that the Sunday meeting is for the public and the mid week meeting is more for the JWs.
So somebody screwed up.
Unless there is a reason why not, the announcement is made by the chairman of the judicial committee that rendered the decision.
So its not like some hapless brother was handed a note and told to read it. It was a definite policy goof.
I know! Lets disfellowship that elder! He was brazen!