And you have to tell that to every roommate, every time they change. And you have to tell that to every guest of every roommate, even those you haven't met. The roommate could bring over a friend, a girlfriend, a random person from the bar. They might update. Or the roommate could forget this. If the roommate is drunk, on drugs, or even just distracted and happy from sex, they may forget an update. I had an expensive limited edition beer go missing. My roomate didn't steal it. But one of the people they invited over during a party stole that beer. That person didn't even know the beer was special. They accidentally stole an $11, can't even be bought in that state, 18%, very limited beer. If they had known that, they probably would have taken a normal beer, but they were drunk and ignorant about this.
Plus, for lots of people, those roommates are fucking children. Children don't understand this so well.
It would take Nintendo not very long at all to fix this problem properly. I don't want to buy a Switch at all until it was cloud saves, theft protection, parental controls, and other features to ensure its safety.