Genuine low km cars do exist, but you have to pay through the nose for them. The problem with buyers who spend top dollar and get genuine low-km cars from Japan is that when the time comes to sell, asking $55K for a V-Spec with a legit 50,000km is impossible when old mate down at Dodgy Brothers is selling them with wound back odometers for $45K with a 12-month warranty.
Simon to answer your question, the question is not where it is done, but who by Export certificates list odometer readings every two years now, which has all but wiped out odometer tampering on the domestic market in Japan (gauge cluster swaps excepted - but even then that is noted).