Notify by e-mail

Is there a way that I can turn on "Notify by e-mail" option by default when I am composing a new mail message to another member? or have this option turned on and not even visible to the member.

Hello, open file - templates/base/mail_box_compose_message.html

find this string : <label><input type="checkbox" id="notify_mail"/>__notify__</label>

and replace on :

<label><input type="checkbox" id="notify_mail" checked="checked" />__notify__</label>

Thank you :)

Is there a way for  me to keep it ON and hide it from the user so they dont un check it?

What about the check mark when you do "Reply"

For reply, edit "mail_box_replay_message.html".