Maggie pours a cup of coffee and leaves the cup and saucer on the counter after taking a drink. Then she locks the door and turns off the lights to close up. She wouldn't have left a dirty cup and saucer on the counter like that. She would have put it with the other dirty dishes usually in a tub behind the counter.
After Barnabas leaves the restaurant Maggie seems to pick up payment for the coffee and put it in the register although Barnabas isn't seen putting it there. (Even when he stands up to leave no money can be seen on the table near his cup where she supposedly picks it up from).