Pros:
more user friendly, only need to remember 2 secrets(location, password) rather than 3 secrets (location, password, protection code). User will not be prompted for protection code when first opening the generate view.
Or make the protection code option, but place a button on the password generation page e.g 'create guard code' . When user clicks, explain purpose of guard code and have user set guard code.
Make protection code optional.
Cons: password could be caught by key logger.
Pros: more user friendly, only need to remember 2 secrets(location, password) rather than 3 secrets (location, password, protection code). User will not be prompted for protection code when first opening the generate view.