In the South East, they bring you sweetened (usually far too sweetened for my tastes) iced tea. This is amazingly universal.
I live in NC and have been probing the border for years.
For “nicer” restaurants, the universal sweet tea boundary seems to be precisely at the NC/VA border.
In Texas, they would ask whether you want sweet or unsweet and you’d get a glass of iced tea. The closer you are to Louisiana, the sweeter the tea.
You have to specify hot tea, if that’s what you want.
Same in Missouri. It used to be that they’d assume sweet tea, but that’s changed in the past 10 years.