Could be abused because somebody could force somebody to listen to something they don't want it for example arrested players. Houses would work though.
An excellent idea, how much I would like to hear the perfect music in my car , especially when I want to play the race !
An arrested player might not like the radio either, so if that's a problem just remove it from arrested players completely.So I don't see anything but good from this. +1 because it's usefull and RP+.