There is a loose conection and one tamagotchi gets tricked into thinking it's connected but the other doesn't connect and it has happened to me many times
I remember when I my first tama died he was 7 and I forgot to look at him for a while and when I next looked he was dead.
The worst time was when my 57 year old tama died it was 7:22:31 and I watched him die I was soo upset.
Oh and Computer WIZ press Caps Lock