At the California Adventure Moonlight Magic last week (11/14/2019), everyone in attendance for the event was given a $20 meal voucher good at any of the quick service restaurants throughout the night.
It was good for a single transaction up to $20 in value. One of my totals came out to $23+change, and the CM very nicely just comped the difference. Another total came out to $20.77, and the CM made me pay the $0.77 difference (not complaining).
To be clear, the event map stated that the voucher was only good for (1) meal entree and (1) non-alcoholic beverage, though really it was good for anything up to $20.