It's a brilliant idea. Radiohead already applied a similar method as well.
I mean, take a look at Beyonce and similar artists who make hundreds of millions through branding, isn't it a bit too much for the effort given? I think all musicians and artists start spreading freely their work once they reach a certain threshold of income.
The problem is how do you draw the line?
But unlike NIN, Radiohead just did it as a publicity stunt. I believe they've confirmed it was a one-off and they won't be doing it again.