If you book a table for 2, the CMs at the podium will do their best to seat the extra person, but there is always the slight possibility that you will not be accommodated because the restaurant is at capacity and the fire and safety code will not allow any additional people. We also saw one restaurant that was running far behind schedule so it was not accepting walk ups, late arrivals or anyone not included in the reservation.
Rather than a table for 2, look for a table for 4. It's always easier to show up with 1 less and you will not be charged the no show fee for the "missing" person as long as at least one person shows up for the reservation.
Because of the no show penalty more reservations are being cancelled so keep checking online multiple times a day to see if a cancellation for 3 or 4 re-enters the system while you're checking. You can keep checking even after arriving at DW.
You can also subscribe to the cancellation thread for your month on this board.