So I thought I'd have a visit to the Starlit Night with my new upgrade card. Sweet!
Unfortunately, I hit my quoin limit two quoins into the Starlit Night experience. And because it's a self-contained experience, my inventory wasn't accessible, so I couldn't quaff a Potion of Avarice.
Result: I spent 5000 iMG and was able to play some pretty chimes.
I think these Upgrade card scenarios ought to be excluded from the quoin limits.
[Update: AND NOW THEY ARE! SWEET!]