I've said this before, having a car in a dealership is no match for seeing a car driven around. Only people that see the car in the dealership are those specifically bothered to go there, IF they know its out - whereas when you see one on the road you are like 'ooh look the new GTI,' which gets a potential customer thinking (far bigger audience) and then they start researching the car, reading reviews etc.
The fact that the earliest anyone will see one on the road other than a test drive is end of July is such an oversight by VW, given their 'on sale June' tagline. Then again, it could be said that as they've clearly sold their allocations up to it seems at least October then their marketing technique is working, so what do I know!