Perhaps tourists expect these cities will be nightmarishly busy and expensive so, unless they are coming specifically for the sport, stay away. People with tickets to events will likely spend most of their time around Stratford - it's possible that around the West End we might not actually notice much difference from a usual summer.
Visit Britain has £1bn to spend on marketing and PR to capitalise on the Olympics spotlight, and also to reassure overseas visitors that the UK, and London, is very much open for business. But looking at these numbers, while the hospitality industry is already working out how to capitalise on a good Games, we might not actually be clawing our way onto the Northern line just to get to work.