I am always baffled by people who take their significant other out on a date with the intention of dumping them.
Breaking up in a restaurant is a terrible thing to do even if you think there's something sentimental about popping into your favorite bistro one last time together.
What you need are some foolproof break up recipes to take care of the situation in private. It's very rude to have someone come over just to send them packing. You should definitely have some wine handy and then be prepared to feed them well so that when you break the news later they are not throwing up an empty stomach.