Neat what does the FAA have to say about that I wonder .
If they disapproved all you'd have to say is that you were listening to find out which station it was. NDB was one of the first radio navigation systems developed for aircraft. The FCC requires a radio station to give it's call letters and station identification info on a regular basis.
In the old days of aviation this was one of the best navigation aids there was. Just listen to the ball game until the station gives their ID then look it up on your map, tune to different station (also carrying the ball game

) and take a reading to that. Triangulate your position from there and you have your location. Big inprovement from the time/heading/speed navigation.