I've been pulled over for exceeding the speed limit (I left cruise control engaged on a decline and didn't brake), and when the cop realised I was driving in state A in a car registered in state B, with a licence addressed in state C, it was all too hard, and off I went.
By your logic, it is legal to drive over the posted speed limit in Australia.
Thailand is notorious for how it's laws are enforced. Earlier today I had to stop and wait (on foot) in a traffic lane, because a motor scooter was driving the wrong way in the parking lane past a police officer, who did nothing.