They aren't going to stop narcocorridos that's for damn sure. Corridos have been in Mexican History since the early 1900's, and they've always touched on popular modern topics for the era they come out. Right now, the Narco scene is obviously blowing up so that's what most corridos are about these days.
You don't arrest the reporter for reporting murders and drug dealing, so why should they arrest Narcocorrido performers and writers? Doesn't make sense.
A little history lesson for you guys. Los Tigres del Norte song "Contrabando y Traicion" was the very first "narcocorrido" song to come out, and Chalino Sanchez was the one that put narcocorridos on the map.