Oh we had a GREAT time wiht that gift card during our February trip! They will let you use multiple GCs per purchase, so when the 3 of us each wanted to buy things separately (always adding up to $50+ each time) and we each got those GCs, we could then buy more with the GCs. The TMs were great.
We saw signs about the promo at almost every shop we were in; if you have a question about it, just ask the TM in the shop you're in if they are participating.
And you can use the discount (well, we could use the AP discount during the time we were there) on the purchase WITH the giftcard as well.
We did some good shopping at Universal.
Just make sure the TM is doing the promo right! I got to spend double the time at one transaction because the TM forgot and didn't key it in right. BAsically they enter in the GC as though you're paying $10 for it, then they reduce it by $10, and in that way the giftcard is activated and given to you. if they don't do that, they can't just give you the GC. She had to get a manager and override it, do the return process on it, and charge it all again. I had already paid it by the time I looked at the receipt and didn't see the GC (which I did because she didn't give me the GC) and I was doing a room charge, and both charges came through so I had to call to make sure I got the refund. So just make sure they are doing it right and have remembered about the promo!