Reservation line is busy, please call again

Robert Cialdini, Noah Goldstein and Steve Martin have written Yes! One of the strategies that they discuss is “if the line is busy, please call again”, tagline in your advertising. What that signals to a potential customer is that you are so busy that even in this day of multiple lines there is a possibility that the phone call will result in a busy signal. If other people are trying to get through to make a reservation that is “Social Proof” that it is a good idea to dine at your restaurant.