@cloud36426 I've never had an issue using the vita and PS4 and we are on the same account

Maybe it's because I don't go online to play but I do remember having to stop using ps now once as he wanted to play online

However the games can still be on both machines much like if you had a cartridge to share in a family

Yes you can't all use I at the same time but all you have to do is take it out and pop it in next machine to use

What I suspect is that Nintendo are only going to allow a game to be on one machine at any one time so if he wanted to play a game in the evening he could but say I wanted to play mine later at night it would have to be uninstalled on his and installed on mine

Seems very stupid if the games are supposedly tied to your account

Surely they can see the game is on a machine with your account

Like I say I'll wait and see