Michael has never been arrested, even ten years ago when the first allegations came forth, he was not detained. Normally, the search warrant is issued, then used to find evidence to get an arrest warrant. To get an arrest warrant along with the search warrant - then there is apparently evidence or good reason to be believe he should be detained.
He\'s currently in Las Vegas doin\' his video, but I would imagine when he returns to LA - he\'ll be arrested.