I (23M) and my friend Jen (24F) were at a Chilis yesterday. We ordered our food and I got a cocktail and she got an iced tea since she was driving. When I got my cocktail I had a sip and really liked it, Jen is picky about alcohol but I felt like she'd like this drink since it was so sweet and fruity. I asked her if she'd like to try a sip and she said sure.
As she was trying it I hear someone quite literally scream "NAWNAWNAWWWW" behind me. I turn around to see that our waitress who took our orders and served our drinks is flying towards us at a terrifying speed. She gets to our table and loudly says something like (don't remember exact wording now) "It is COMPLETELY ILLEGAL to drink someone else's drink."
I understand how they may assume my friend was underage because we are near a college campus and since she ordered a tea, they never ID'd her. So of course Jen immediately says something like "Oh no no don't worry, I'm not underage" and pulls out her ID. I assume this is the end of it but somehow this seems to make the waitress even madder. She doesn't even look at it but insists that since she didn't ID her at the beginning, and since she was drinking a drink without being ID'd beforehand, that what we were doing was a "federal crime" (her words) and that she could get fired.
I feel like that wasn't correct and tried to say that I don't actually think that was illegal. She interrupts me and points her finger at the door and says we were being belligerent and would need to leave. I told her that we hadn't even gotten our main course, we only had our appetizers and drinks, and we hadn't even paid for those yet. She gets a blank look on her face and tells us to stay there and disappears for over 5 minutes.
Then a guy approaches our table, I assume the manager, and asks to see my friends ID. She shows it, of course it's fine, and he apologizes and says our drinks and appetizers would be on the house and that our main courses would be out shortly. At this point I was feeling very confused over what the hell just happened and just wanted to leave so I asked if we could get our mains to go. I then asked what happened with our waitress and this seemed to irritate him which confused me further, he flapped his hand and walked away while saying "miscommunication".
We paid the rest and left and didn't see the original waitress again for the remainder of our time in the restaurant. I tried to do some research online and see if what she was saying was true, that you can't drink if you haven't been ID'd first, but couldn't find anything about this. If that is a real law (I live in Arizona) then maybe I was the asshole for insisting she was wrong or allowing my friend to have a sip of drink at all. In my head though it's fucking ridiculous that my friend who is almost 25 got screamed at for having a sip of a drink, especially so when she immediately provided her ID when she was questioned.
So, AITAH for letting my friend have a sip of my drink?
Edit to add that all I said to the manager guy was "Uhhhh, is everything okay?" after the incident, and that's when he seemed a little upset, though I could have been misreading the situation. I wasn't trying to get anything else, I genuinely was unsure if I had actually broken a rule or what in the world had just happened. I was also on the verge of tears because i am autistic and the sudden loud noises and confrontation really upset me which is why I wanted to go home. I was not rude to the manager and was not expecting anything else from anyone.