Confirming Reservations
Now this doesn't always help and some restaurants that are suffering from no-shows do actually call the guest to confirm the reservation. But it is a minimum and gives the guest an easy way to cancel. Maybe making the call a bit personal, asking about dietary requirements, special occasions etc may help build the relationship between guest and restaurant. But of course with most people who confirm the reservation and still don't show up this probably still won't help.
Over Booking
We bet most restaurants already do this, such is the problem of no-shows. Overbooking by a couple of tables each night may help offset the damage caused by having empty tables.
Credit Cards
Asking for a credit card when taking a reservation, along with having a clear cancellation policy, could help curb this problem. It is common enough in other cities to do this. When booking, a credit card is supplied and the cancellation policy is clearly communicated to the guest. It would usually be: cancelling with less than 24 hours would incur a cancellation fee. The restaurant would then ring to confirm the reservation 24 hours before the booking to allow the guest to cancel with incurring a charge. Asking for a credit card to secure the booking will make diners more likely to honour it. This is common enough with well established fine dining restaurants - Patrick Guilbaud is the only restaurant in Dublin that we know of that asks for a credit card at booking time. The bigger the reputation of the restaurant the easier it is to implement this system. Last time we booked Restaurant Gordon Ramsay the cancellation policy was £150 per person for not cancelling in time. It is not as usual for a new or casual dining restaurant to ask for a credit card, but maybe it needs to start be the norm. It is understandable that new restaurants don't want to ask for credit cards as they don't want to appear standoffish or unapproachable when they first open. But certainly group bookings should have to be secured with a credit card or even a deposit.
Online Booking
Online booking facilities, such as OpenTable, can make asking for a credit card easier as they are supplied through the online booking form. It also makes it very easy to clearly show the cancellation policy, both at booking time and in the confirmation email. These can be easily integrated in to a restaurant website, but the downside is that this service does cost. In many cities online booking is the standard, but for some reason this has never really been adopted in Ireland, although a few restaurants are starting to use it. Also OpenTable will cancel a user's account if they no-show 4 times within a year.
Easy Cancellation
Making it as easy to cancel as possible may result in more cancellations and less no-shows. An online booking system might help this as the reservation can easily be cancelled online. People may be more inclined to cancel online rather than have to ring up and talk to someone.
Name And Shame
Maybe restaurants should start naming and shaming guests who no-show. A sort of blacklist could be maintained that all restaurants can easily access. This may make people think twice before deciding not to show up. Even a twitter account that tweets the name of the guest who made the booking and didn't show up may help. This has been done in Montreal with the twitter account "NoShowsMontreal". Even better would be an association maintaining a database of serial cancellers. Restaurants could check names and phone numbers against this list at time of booking. At a minimum restaurants should keep their own list of no-showers so they can catch them when they try to book again.
Ticketing
Currently there are very few restaurants in the world that would get away with a ticketing booking system, wherein you pay for the meal when you make a booking and receive a ticket for the reservation. Alinea in Chicago were the first big restaurant in the world to adopt this, but it could be about to spread. The inventor of the ticketing system that Alinea use, Nick Kokonas, is launching a system that can be used by any restaurant. It may be the future, but probably only for the small amount of restaurants around the world that are big enough, like Alinea, to have a huge demand for reservations.
There maybe no perfect solution to this problem that doesn't have a downside, but it is a growing issue and needs to be addressed before it actually kills a restaurant. Communicating a clear cancellation policy, confirming reservations and taking credit cards or deposits for group bookings is a minimum. People may not realise what it means to the restaurant when they don't show up for a reservation. If you are reading this and you have not honoured a restaurant reservation before, maybe think about the consequences before doing it again.