What's wrong with this picture?
Fast Food restaurants always take your cash or credit card first- before any food is served up!
No need for Fast-Food workers to be rude to the customers unless they ask for a handout or something!
Now I know Chipotle has a help yourself food line, where you get what you want and pay at the end of the line.
But, unless the Restaurant has some kind of evidence that someone has ever refused to pay at the end of the food line, then I can justify their refusal to allow them to return to the restaurant.
That is usually handled by management though!