I've had the Watch ESPN app installed on my phone for a few months just in case forgetting to ask a friend for his login. Opened it today on my Nexus 4 and I can watch ESPN and ESPN 2 programming with a powered by Dish logo on top. I never logged in inside the app but it appears that logging in for the NBC Sports Live Extra app last month also has me logged in for this app (they use the same powered by Dish logo).
So maybe it's the fact I've had it for awhile or maybe because I logged in through a similar app or maybe it's just luck.
Edit: tried it on my tablet. Installed it from the Play Store, opened it and everything was locked, nothing to view as I was not logged in. Opened the NBC Live Extra app, logged in with Dish. I then closed the WatchESPN app (with the recent apps button in Android). When I reopened the WatchESPN app, everything was unlocked and powered by Dish! Of course, YMMV and this loophole could be closed at anytime. This was done on an Asus Transformer Pad running Android 4.3.