The way it was explained to me during my demo drive yesterday:
After placing the non-refundable deposit, as part of the pre-delivery checklist you'll be offered a few possible delivery dates. [I put my deposit down yesterday and was offered this Saturday, Sunday, or Monday - a variety of 15-minute spots on each day. I've seen/heard other people being offered just one time on one day]. Can't keep the date you choose? You can push it once to the following day. Can't keep the pushed date? You can push it one final time to the day after. If that doesn't work either, then (1) the car is released; (2) your non-refundable deposit is lost; and (3) a hold is placed on your account for 7 days during which time you cannot place a new order. After that, you can start the process again if you like.