Other mistake: Maureen gets popcorn and a coke, yet doesn't pay for it. Nor does the cashier ask for money. (00:04:45)
Suggested correction: We are not shown her hands. She could easily have put the bill on the counter. If we saw her hands the whole time and she did not pay, it would be a mistake. But if we only see her face, how can we assume what she did with her hand? After all, we do not see the hand. It is off-screen.
Suggested correction: To be fair, she asked her boyfriend for some money, he gave her a note, which she holds in hand in that scene making her order and, almost certainly if we go by the arm movements, puts on the counter. If what she ordered required no change, nothing more was needed in the exchange. It's not as if she just went to the counter, didn't have any money with her, was fully on camera all the time and got her order sorted.
