I was waiting for someone to suggest that! 
However, some of us like to leave our shiny wonderful gear unblemished by electrical tape, even if it does result in the annoying blinking light.
And honestly, I wouldn’t mind covering up an annoying light in some situations, but this one is actually a useful light with Cubase, since I know that Cubase is connected to the CC121 when it runs… so it serves a purpose. Just wanted to see if it was quick and easy for PG to add such a feature to WaveLab as well, but it looks like it may be more hassle than it’s worth.