I've noticed this. Anywhere I've seen an iced tea tap next to Coke, Sprite and the other soda taps, it's usually tea syrup mixed with water and dispensed. No thank you...I prefer my iced tea properly brewed...and unsweetened, although I have been known to enjoy a southern sweet tea from time to time. :)
Our machines used giant commercial sized tea bags of real tea. You’d stick a teabag in the compartment, hit the button, and the machine did the rest. It brewed really good tea actually, though to me the sweet tea was too sweet. I know there are some places — like Subway I think — that use the Nestea tea syrup, which I agree makes for some really foul tasting “tea”.
The biggest problem with ordering unsweet tea in the South is that relatively few people drink it, and so it tends to sit in the machine longer. If the machine’s urn hasn’t been meticulously cleaned, which often seems to be the case at fast food places, the tea can pick up kind of a funky algae flavor. Whenever I go somewhere and they have good unsweet tea, I know that they keep their tea urns clean. And since cleaning the urns is an easy step to skimp on, I consider this is an indicator of good management and attention to detail. If the unsweet tea tastes good, I’m inclined to think the the kitchen is more likely to be clean and sanitary.