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.
Europe.
Either they ask back wether I want hot or ice tea (beverage) or they default to hot tea and bring out the tea arsenal in a small box to choose.
so if you want the beverage (ice tea) you should say that you want ice tea.