yeah this is the worst part. it really eliminates a big part of the GO aspect. When i am traveling and my team isn't being locally broadcast i want to be able to open up the app and watch my team.
I switched from SlingTV to PSVue and it's been great. It's more expensive but completely worth it. I can sign into the apps for my local stations (ABC, NBC), cable stations (TNT, USA) and sports (FoxSports Go, ESPN). It's like having a cable subscription without cable fees, contracts and equipment.