Wouldn't this just be a matter of stopping the audio or closing the browser tab? BBC's iPlayer works through the computer's own sound system, hence is easily controlled. I've listened for years, on both Mac & Windows laptops, iPads & other mobile devices, and never had a problem. So I'm not sure how it could interfere with Noteworthy in any way that couldn't be easily switched off, if two sound sources ran simultaneously...? And if you listen to radio independently, without the music software running?