nope my clients doesn't give me their fb account(s), i create fresh pva account everyday. But if i asked to verify account i have two option:
1. give them the phone numbers, so they can enter the phone number by themselves, and then i tell them the code that fb sent.This option is much comfortable but take more time to do.
2. i verify their account, will ask for login,password and dob. This option is less comfortable but faster to do.To keep everything safe, password for email account associated with the accounts should be different than the fb password.So when someone evil (no..its not me lol) change your fb password you can always reset it back.