Yes, in order to get the GC you have to do the pre-order. I am on my way to work, but I will search for the slickdeal thread when I get there and post it.
I just found it, thanks! I am cutting and pasting this scenario from Slick deals (so the credit goes to a slickdeals poster on this) for anyone interested and assuming the prices are correct for Beauty and the Beast and TS when they come out.
Transaction 1:
10.00 Tinkerbell Deposit
Transaction 2 (when Tinkerbell is released):
$24.99 Tinkerbell
+$5 Beauty and the Beast Deposit
+$5 Toy Story 3
-$10.00 BATB discount for Preordering
-$10.00 TS3 discount for Preordering
-$10.00 Disney Coupon (will hopefully exist)
-10.00 Tink Preorder (deposit from transaction 1)
+ 0.00 $10 Giftcard given from Tink Preorder
+ filler ( should be $5 or more to avoid negative balance but if the movie is $29.99 you won't need this)
-------------------------------------------------------------
-$5.00 Tinkerbell & BATB Preorder & Toy Story 3 Preorder
Still have $10 gift card
Transaction 3 (When BATB is released)
$24.99 BATB
+5.00 Toy Story 3 Preorder
-10.00 Toy Story 3 Discount for Preordering
-10.00 Disney Coupon
- 5.00 BATB preorder
-5.00 Apply Tinkerbell giftcard given in last transaction
--------------------------------------------------------------------------------------------------
$0.00 BATB and Toy Story 3 Preorder
Transaction 4 (When Toy Story 3 is released)
$24.99 Toy Story 3
-10.00 Disney Coupon
- 5.00 Toy Story 3 Preorder
- 5.00 Apply remaining $5 from giftcard from Tinkerbell purchase
=$5
Hopefully this will help someone and that it makes sense!