The mock draft does give you commish powers. There is an undo button and a Commish Draft button. For the live draft, for teams not logged in, they will be automatically picked for within 5 seconds (usually commishes pause the draft and make the pick or undo it if it moves too quick). In short, you can do both.
Awesome. Always the answer I am looking for whenever I ask a question here. Really looking forward to the season. Thanks guys and gals.