For the confusion:
I know this to be 100% true:
You can choose to disregard what I say but what I’m saying is 115% correct
If you downloaded Mario kart as user appleJuice7 then any switch logged in as appleJuice7 could download Mario kart
Only the switch that was appleJuice7’s primary could launch the game without ANY checks. And any other user on that primary switch could launch it. So your brother, mapleSyrup5, could play your purchased game via his user account IF HE LAUNCHED IT ON appleJuice7’s primary switch.
Any other switch that was logged into appleJuice7 (and was thus a secondary console) could only launch the game via appleJuice7 user profile. So mapleSyrup5 could no launch it. Any other user on that console was blocked. The launching of Mario kart ON THAT SECONDARY SWITCH (NOT PRIMARY!) needed a online check to verify that no other SECONDARY SWITCH was playing any other game from appleJuice7’s library. If another person was playing via appleJuice7’s library on another secondary switch then they would be logged off as a consequence of you trying to boot a game on a secondary Nintendo switch console from appleJuice7 library
Even if the other person was paying Mario Odyssey and you were trying to launch splatoon to Mario, Odyssey person would be logged off his session
The primary console will never be kicked out or logged out! The primary console always has had no restriction.
Now if the primary console was completely offline and you tried to take one secondary switch logged into appleJuice7 and another secondary switch logged into appleJuice7 you would thus not be able to play Mario Kart online against each other as one booting the copy on Mario Kart 8 would immediately throw out the other secondary switch from their Play session
However, if the primary switch launched Mario Kart and you tried to launch Mario Kart via appleJuice7’s user account on a secondary console then you were totally able to play with the same copy of Mario Kart 8 against each other.
My brother and I did this for years on every single game that we played online. Since the secondary console is only able to launch games from the user who purchased the game my brother would be logged in to my account as the primary console so that he would be able to launch the game from his user profile. I would then log into my own account as a secondary console. I was always only able to launch my purchase games via my user account (meaning if my girlfriend wanted to create her own user on my switch she wouldn’t have been able to launch my games) and always had to do it all night check before booting my game.
This made sense for me. My brother as mobile data is very reliable in the United States but very reliable in Germany and I live in Texas and he lives in Germany. So it was very nice that he did not need a online check to launch the games and although it was annoying that I had to connect my switch to my phone every time, I wanted to play something for about 10 seconds to do that online check.
My brother would play my games with his user profile as my user account was logged into his switch and his switch was set as the primary console.
