To all appearances even THAT didn’t happen, doubtless due to some corporate rule about not going out when a difficult customer shows up, because of the litigational dangers.
They know her license plate. It’s sitting right there in view of the order window. Just phone police and let them take care of the unruly customer afterwards, with disorderly conduct charges or whatever.
I would think that rule would mean don’t go out and deal with the difficult customer. I don’t know that however. Alternately they could close the pick up window and take money at the order window. Yes, it would be difficult for them, but it would serve their customers. (Do this having called the cops of course). My thought is that if they serve her and call the cops she will be long gone and the cops will have to go to her house or pull her over somewhere simply to accuse her of cutting in line and to tell her not to do it again. I doubt if this is a big negative to someone who is willing to sit there for such a long time and to still be so adamant when the cops show up there. She would have already gotten the reward she wanted which was not the food itself, but being first in line and bullying and getting her way. It still “worked” from her point of view. Classical conditioning. Punishment after the fact is less effective than is removal of reward. The punishment of talking to the cops later on is so far removed from the behavior at that point that it isn’t very powerful to someone so “off”. To a normal person, maybe yes, this would be a deterrent. She seems far from normal.
In theory, you're right. But the woman would just deny everything. Without a cop as a witness, it just becomes a he said, she said kind of thing.
And of course the woman's daughter would back her up.
If McDonalds had done as you suggested, I could easily see the woman getting off. Then would come an expensive lawsuit against McDonalds.