You pay through the app, card only. When the girl came with my water, they just handed it to me and that's it.
First, you don't "pay through the app". You must forgive me, I am being very technical here because it's what I do (and before this I ran restaurants for a fortune 500 chain for 11 years, so I see an odd blend of the tech and operations sides)...
Anyhow, I'm being technical, but it's worth noting, you don't pay "through the app"...technically...you pay through the payment gateway Disney uses. The Nack/Ack must come from that. The app is merely the GUI.
I apologized in advance cause I don't want to make it seem like I'm being obtuse or attacking your experience (rather, the latter, I love that you've experienced it and have first hand knowledge as a user!)
As far as operations...perhaps I'm confused...
They didn't confirm it was your order?
I thought you said they did?
And, I thought you said you were not charged until AFTER your order had been delivered, which means that a call has to be initiated after delivery (though, that doesn't have to be done from a handheld device they use, rather could be done from a system back a "main base")...
A pre-auth, then final charge setup is inefficient for cost reasons regarding payment gateways. It's better to just charge outright for low dollar, high volume, transactions, and Disney easily knows this.
The point is, I was going off your specific description of how the system "works"...