Depending on the time of day you're listening to the radio, the playlist can be very short. It's not uncommon to rotate the same dozen high-traffic tunes during the evening hours. Try guessing the next five songs and getting them all right, instead of 12 out of 20, which is 3 out of 5--pretty good, but not supernatural, considering the nature of mainstream radio these days. The current playlist for Live 105, the big modern rock station in San Francisco, is only
37 songs. When you get familiar with a station, it's not unusual to be able predict the songs during the high-traffic times of day.