Not gonna argue with the overall hypothesis, because you make some valid points. Except the Sage bit. Sage clearly hides her face, because she just admitted Tremolo fucked her in the butt, with the waiter standing next to her.
Then she said she wasn't coming back because she said she was going to fuck MC tonight, with the waiter standing behind her.
She was clearly embarrassed, not because of who she may or may not have seen walk in. That's a stretch for me.
I do think all your other points are worthy for consideration though.