At least in the US I've noticed pre-brewed iced tea has often switched to some sort of flavored tea (or a fountain drink). My best guess from working at a plac

At least in the US I've noticed pre-brewed iced tea has often switched to some sort of flavored tea (or a fountain drink). My best guess from working at a place that had pre-brewed tea is that they're hard to keep clean and people tend to like novelty. "Normal" (black iced) tea can taste really gross if the container isn't cleaned properly (or the water is bad quality). I've also seen where the container was soaked in chemicals and not washed out well. "Flavored" tea would mask this. As for hot tea, unless you're at some specific restaurant where the default is more obvious I would at least expect "black or green" if not Earl Gray or a few other choices.