I finally found out what happens if you are in sleep mode in a game, then start the game up on another switch tied to the same account. then, play the game and save (what happens to the cloud save for the first switch). a message will pop up saying that a new save has been detected, on the first switch, would you like to restart the game using the new save? if you say yes, then the game restarts with the new save(s). I had always wondered this, but I did this accidentally one day a week or two ago. I think I asked on here, but didn't get a response, so now we know.