Yeah, I think it comes down to how the app handles it. I have 3 GPS tracking/logging apps on my Nexus and I just launched them to see what happened.

-Endomondo opens up to the 'start activity' screen and the GPS kicks in automatically. Leaving that screen to view 'history' does not turn it off.
-Sports Tracker opens up to to a display of the aggregated data from all workouts. The GPS turns on when 'start new workout' is selected, but turns off if you hit the back arrow. So no GPS just to view stored data.
-My Tracks (Google product) doesn't turn the GPS on until the start button is hit, either.