@Xaelath It was the author yeah. I guess it made the joke of artist because typically the manga is done by one person and it doesn't want to outright connect the joke to the actual real life case.
I remember they did this back in the 90s because the bottling plant was in the city and if you brought the glass bottles back to have them refilled, you got a discount.
I remember Squirt, 7Up, Fanta, and Coca Cola was big at the time