It is a given fact that in a TT installation any fault Live to CPC between the incomer and the RCD is unlikely to operate any protective device. The CPC will be at Live potential, every appliance will work normally and inside the "Faraday cage" of a perfect equipotential zone people will be not be at risk of getting a severe electric shock.Not with a TT installation where the live-case fault is upstream of the RCD.I can't see a single fault increasing the risk. It would require a Live to Case fault and a loss of earth to the case before the case became live.
But there will be steep voltage gradients around the ground rod and the risk of receiving mild to serious electric shocks as a result of these voltage gradients is significant.