Asking for email (plus other things) is unecessary and a risk. You should only ask for and trust information once someone has been authenticated.
Don't we use our email address to sign up here? What is the difference? Is it because the email is being linked to the AAWA Website and to the Facebook Group in conjunction? Facebook requires email authentication as well. If the emails don't match that would be the first red flag once a Facebook Profile has been researched.
Other websights allow Login utilizing Facebook Accounts for authentication. Maybe that would make more sense.