The decorations were only at T2 and T3. If you are looking for the fastest way to get to robe fitting, you can follow what I did.
You have to take 3 photos of yourself at the following event areas in T3 then post them on either Facebook, Instagram, Weibo or WeChat using #ChangiWizardingWorld.
The next step is to return to the Diagon Alley event area to register yourself for either of the 2 activities or the Surprise Giveaway which I feel that the prizes aren't attractive unless you are in a rush of time. Do note that you need to present your social media post with your NRIC and download the iChangi app.
For the 2 activities, you can choose either:
Set A: Robes Fitting + Wand Challenge
Set B: Quaffle Toss + Niffler Challenge Game
I picked Set A since I get to dress up as a wizard and have the GIF e-mailed to me.
After registration, I got the house stickers which I don't know what I can use them for yet.
You do not have to really queue at the robes fitting because the staff would be calling out queue numbers. Just stand by outside the activity area with your ticket.
They have robes for the kids too so do check before you put on cause I was one of those who only realised after I put it on.
Each registrant gets to take 4 shots for the GIF so for example my friend and I would get 8 shots in total.
We didn't go for the wand challenge since it was just playing with the wand in front of the mirror.
Time to talk about merchandise which can only be bought at T3 event area next to Hogsmeade Village. The stuff aren't cheap and not interesting enough to me.
So how to get the Gryffindor scarf? First criteria, you have to be a Changi Rewards member. Second criteria, purchase $60 worth of anything at the public area in a single receipt. For supermarket, you will have to accumulate $120. Signing up as a Changi Rewards member is free so why not?
I bought the Sulwhasoo Cleansing Foam Ex Duo at $61.90 from the Sulwhasoo counter at public area and headed to B2 event area with my receipt, promotion paper (given with receipt) and my Changi Rewards e-card. I spent an additional $15.00 to get my long-awaited Gryffindor scarf.
If you are looking to get into Christmas mood, you do not necessarily have to be at Orchard now. Changi Airport is a good place to chill, shop and dine. I am starting to appreciate our airport as I traveled around the world.