I have had my S7 since ~April, but the daily (sometimes multiple times/day) update of GameService only started ~one week ago. I have now force stopped the app, but others experience suggests this will do nothing. I could also turn off the notifications, which might make the updates less annoying, but that doesn't change the invasive nature of these updates.
I did not have/play any games UNTIL ~one week ago, I installed the 'free' GearVR that finally arrived. I downloaded the free apps (system and yes, games). I tried the Gear long enough to realize it would not work for me because I have very very different vision corrections required for my 2 eyes (no contacts). I have not touched it since ... but I wonder if all the Oculus Gear software installed/enabled that GameService app? I guess I could try disabling or removing all that Oculus stuff (but I'd rather not try).