I made an Android game with Google Play services implemented. I tested a game on my device and it worked perfectly well by signing in only once.
When I published the app after testing it like hundreds of times, I tested a game on another device and found out that when the scene resets it signs in the user over and over again.
I thought this is taken care of by Google Play plugin, but apparently I was wrong.
The only way I can think of is to have a loading scene when the app is opened, that is never called again during the rest of the game session (i.e. first in the Build Settings list and never reloaded).
I’d love to hear from more experienced people about how Google Play services are usually implemented in terms of when to prompt sign in, dealing with connectivity issues and errors etc.