Yes some of the reason for that is so someone just doesnt turn on a station, mute it, and play if for days on end.
It is a bit of a pain but they do reward as long as one keeps telling the system they are alive and not just a robot trying to milk tokens.
I know they have their place and I've done captchas before when I experimented with faucets but they have the most annoying one by far, I'm sorry to say :)