I've never heard of this, actually.
That's a good thing. It means that you live a healthier lifestyle than the rest of us. People with the knowledge that the drive through is open much later than the dining room typically don't come by that knowledge vicariously.
Agreed. There are two kinds who go to fast food places late, drunks who walk up or drive up to the window, like our good friend angus, and criminals. To encourage the former and discourage the latter, they close the inside seating earlier.
When I used to live in New Orleans many fast food places had all the workers behind bullet proof glass. They have a rotating window thing so they could give you your food at minimal risk.