It used to be announced in all the congregations they were known in in the late 60's and early 70's. I guess they didn't want to make people curious in other congregations and stopped. In the last 5 years I attended, I heard people announced I had never seen at the meetings; that made people curious.
They stopped that about the time they stopped announcing what the specific sin was they were being DF'd for.
But they make the rules and I think when "apostasy" is involved and the person has connections with several congregations they might make multiple announcements.
Notice they never announced Ray Franz in any other congregation but the last one he attended that I know of.