Phone lines open at 7am EST, online system "rolls over" to the next day at 6am. So by using the online service, you gain a 1hr head start (but have to get up earlier, which doesn't work for everyone

).
For CRT*, it depends. If you have a confirmed resort reservation with an applicable dining plan associated with it, they'll take your CC# and use it as a guarantee instead of a pre-pay. If you cancel less than 48 hours ahead of time, or simply don't show up, that card will be charged the full amount of the meal.
Note that this doesn't always work properly online, and if you end up booking in that manner, watch for the "Amount due today" line before your final confirmation. If that says anything but $0.00, that will be charged to the card right now. If this is the case, you'd have to cancel out of that booking and call.
*The same goes for the dinner shows (HDDR, SoA, and Mickey's Backyard BBQ)