NNID will now be also locked to a single 3DS at one time, so if you happen to lose your 3DS, you will lose the ability to use that same NNID on any other 3DS because Nintendo has said they don't have the ability to remotely remove it from that one 3DS that was stolen/lost/whatever. So, great going Nintendo 😉 Even if they somehow did make it available for you to log into another new 3DS with the same NNID, you will still lose all your purchases at least.