Of course, based on the trailers we know that David finds himself inside an asylum at some point, so it appears that not only will David Dunn be seen by the public, he’ll actually be apprehended at some point.
Exactly what David Dunn has been up to for the last 19 years, we don’t really know yet.
One assumes he has continued to play the hero, but if he’s only being named 19 years after the events of Unbreakable, then it would seem he has done a solid job keeping out of the spotlight up until now.