Yep, another urban legend.   As stated above, there is no way to "ban" a song from public airplay - at least from a government perspective.   It is very possible for the owner of a station to blacklist a song if they choose. In this case, just as in the infamous urban legend from 9/11 where Clear Channel was supposed to have banned a list of songs, this is probably more of an instance where station management urges their employees to use common sense and good taste in a terrible situation.   It is routine for networks to pull airline commercials whenever there is a major air disaster. It is also common to have station management remind employees of sensititivy issues during times like these.   Frankly, there are a number of songs that I would not play in the days following Hurrican Katrina, and I work for a non-commercial station that did not send out such reminders.

I'm not a fan of Clear Channel - they have ruined radio in my estimation.   However, I am really against people getting sucked in by these urban legends and creating misdirected illwill. It takes the mind off the real issues.