I'm gonna guess it's temporary; I get the impression GitHub likes to test its changes before it releases them (I've been seeing the announced license indicator for several days), and that probably goes extra for logged-out users.
Yeah, I have been seeing it for a few weeks now and was actually looking for an announcement - I thought it was a bit weird when I didn't find one. The indicator not being shown for non-logged in users is probably just a consequence of a staged rollout.