The MyHeritage user interface for inviting new members can be confusing at times, especially when you haven't done it for some time and there are a lot of family members looking over your shoulder whilst you are trying to do it. Recently I apparently put an email in another person's box and clicked the Add button. When she logged in after receiving the invitation email, she was identified as another person! This has caused me a lot of embarrassment and grief to the invitee.
Since administrators cannot rectify this mistake themselves, might I suggest that a pop-up appear to confirm the correct person is being invited, ie associated with the email just entered.
Note for designers: On the Home page, from a User Experience point of view, what I see is the Invite close family heading, the Enter email box, and the Add button. I do not register the person associated with the email box.