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.
Chicago: Asian restaurants will bring you a pot of already-brewed, ready-to-drink hot tea. So will nicer Western restaurants that have an actual tea program. Coffee shops and mid-tier restaurants will typically give you a cup with the tea already brewing and it’s up to you to remove the bag or sachet in a timely manner.
Everywhere else brings you a little tea-making kit consisting of hot water, teabag(s), and maybe lemon and honey. You have to ask if you want milk, except at oldschool diners.
Good point. There’s definitely that variation in certain restaurants.