Soda savings

Believe it or not…this was suggested by a restaurant owner that my partner and I share a refillable (bottomless) soda pop rather than buy 2 sodas. We still both drink as much as we like. For the more squeamish (or heavy lipstick), with a pocket knife cut another X in the lid for a second straw if you like. Restaurants pay very little for commercial pop machine beverages and charge a very large mark up that would seem like gouging. Of course this may not be for everyone. One could use some of the change you save to tip bigger?