How can you restore a password in MultiBit if you are given the wallet words BEFORE you even enter a password? How is it possible to recover a wallet password when the wallet words are provided before you even enter the password? 

https://multibit.org/en/help/hd0.1/restore-password.html


  Restore password
  
  If you forget your wallet password, then you can restore your password from your wallet words.
There is a copy of the password stored encrypted with an AES key derived from the wallet words.

Thus if you forget your password and still have a copy of your wallet you can use your wallet words to recover your password.