Tourist,
My last comment was made somewhat tongue in cheek so apologies if it came across otherwise.
One important aspect to take into account with respect to flying over roads, houses etc is that it is actually the flightpath vector of the aircraft that is important. If an aircraft in level flight and with forward speed is going to crash, the point of impact will most certainly not be directly underneath it, irrespective of its height. Therefore, if an aircraft overflies a congested area with a level or shallow flightpath angle, the probability of hitting that area is low. However, steep flightpath angles, such as those that occur during a loop, do present a significant risk of impact with what is directly underneath the aircraft if the manoeuvre deviates excessively from the norm.
The problem with flying low and fast over roads, populated areas etc is that the sudden noise may induce accidents or trauma for those overflown and, in the case of roads, provides a distinct distraction to drivers. These considerations are what often dictate the restrictions imposed at air displays. Therefore, whilst the biggest risk of an aircraft crashing on a road may be the approach case, low and fast overflight of traffic may well be a greater cause of road traffic accidents. I accept that this discussion mostly is not relevant to Shoreham but since we have been discussing safety issues related to the overflight of roads I thought that it was worth raising.