Your comments

I understand completely, But as a integrator that working on projects i can tell you that most of the time the customer is not at home or want us to give him a finished product loaded on his tablet, if you don't want to use his email address you have to create a new one for registration

So for now i think that i will open a Gmail account for each project,

Because the clients are not always in the house and they cant give us there Email passwords.

we should think of a better solution ...