Part of this job is to see if they start rolling up the rugs and setting the chairs on the table. They can pressure you to leave with more subtle ways such as walking up to you and saying, "Is there anything else I can get for you?" They are not allowed to start closing the store and must leave the door unlocked until it is actually closing time and not 5-10 minutes early. They must keep the flat top hot and be ready to drop one last set of patties till the bitter end.
I did one of these where they closed early, turned people away, rushed me out, had the rugs rolled up already and cooked my burger with soapy water all over the kitchen floor at 30 minutes before close.
The next time I went to that location, all the faces in gray shirts as well as red had changed.