This is probably referring to the refreshers and teas. We dilute them half with water because they’re super concentrated/brewed double strength to save space. The shakers that we make those drinks in have lines where you’re supposed to fill each liquid up to with the refresher base or tea usually being first so if you ask for light ice some baristas might just give you extra water out of laziness. I don’t blame them but I usually try to keep the ratio of juice/tea and water proportional.

guess it depends on if the store you're ordering from pre-cuts their cold brew. either way if you ask for light ice, the cold brew won't (shouldn't) be diluted. the post is just a joke

You shouldn’t be getting charged extra for light ice. For cold brew, it usually comes out of a tap now so it’s pre diluted with a specific amount of water and the barista just pours it to the top line in the cup.