https://www.cbsnews.com/news/mcdonalds-free-refills-start-charging-no-self-service-drinks-franchises/
as an example 2 refills for 1.00 as an addon item to allow 2 extra pours similar to low-cost items or deals like $1 coffee or $1 menu items
will only dispense when verified with register like an electronic door key usually associated with hotels or debit card payments where a card can use an rfid tap to touch payment BUT using a serialized programmable QR code to show the cup as an active paid purchase for a refill to receive soda from payment or repayment for refill
paper disposable QR activated from magnetic wand next to register on blue square on disposable soda cup won't activate to pour the size of liquid per.cup if 12 oz code then one shot of 12 oz liquid etc
to activate size of liquid to pour hold above selection of drinks in the left lower corner near push for ice or lower right corner near push for ice and
with digitally reading the code activated from the side of the cup that is a serialized QR code activated by a LAN (local area network) website from the restaurant acting as a web server to keep track of drink cups activated per restaurant
water spout is free no code always pours