If one is the proprietor of a restaurant that is open 24 hours per day, one might be concerned about patrons who, perhaps, overstay their welcome. Here are some excellent solutions, that I have encountered, to this vexing problem:
1. Play sappy love songs from the 1980's on a loop. A very short loop.
2. As an alternative to #1, play a radio station with static sufficient enough to be audible but not to drown out the music completely.
3. Invest in seating that discourages lengthy use.
4. Put your staff on a table-clearing schedule sporadic enough to attract flies to the unconsumed portions of food left on the aforementioned tables.