That is incorrect. There has been an international arrest warrant out on Polanski for 30 years. You make it sound like the LA District Attorney just decided to file for the arrest warrant which isn't correct.
It isn't? well, that's better then. It did indeed seem to me as if the LA district attorney just filed it last week, since Polanski was moving freely. Pops up the question why they didn't arrest him before if the warrant was out?