ODO tempering is not considered crime in Pakistan while it is. ODO is only changed legally if someone changes the cluster and wish to change to original readings. For this reason factories allow to change it but not through OBDII but an enhanced tools normally used by OEM service vendors, but with Chinese equipment in the equation, many has hands to it freely, some cars are easy to temper, some are bit harder but most will keep this odo change in their logs of ECU - unless that is also flashed.
There are other little things can be done to minimize this at government level, record odo mileage with every registration, accident, token payment, change of owenership etc. so over the years a record can be available from registration authorities. This can also be topped up with odo readings from OEM or registered service centres records of the car, same goes for leasing, insurance, tracking companies. All this data can make it mileage record, a company or companies can offer service by sms/online/etc by retrieving from various sources a history of car! Buyers can get such reports by paying some fee. Dealers can offer free reports to build confidence of buyer!
This is already in place in several countries. its like credit history of car!