I had to delete my Mum's user account on my Mac this evening due to an issue with the cursor. I then created the user account again using her email address. BUT then when I went into the App Store on her account to update a couple of Apps, the user email address that popped was mine and not hers. Fair play, I did need to enter my password to update the apps, which I did and then promptly signed back out again. Surely this can't be right, can it???