Our sister paper Seattle Weekly has a fascinating exploration of powerhouse indie label Sub Pop as it considers what is often misleadingly called "pulling a Radiohead" and giving away all of its music for free (if you pony up for a Superfuzz Bigmuff T or a God's Balls beer koozie). Kurt Cobain would probably approve, and so would experiential-based music entrepreneur/Devo drummer Josh Freese.
In a nutshell, this has already been going on for a while -- vinyl copies of albums sold by numerous indies have included download codes. Artists including HEALTH and OK Go have already started experimenting with the "T-shirt gateway to music," but no one took it quite as far as Mos Def's The Ecstatic last year, which was actually released as a shirt. Plus, there are plenty of people who would probably wear this shirt who never need to hear another Fleet Foxes song.