It’s the cameras on the road catching you, not radar. Just pay attention to the routes you drive and avoiding speeding around those cameras.
I live in Vietnam too and I’ve never not been able to bribe the police for any traffic violation. No matter what you did and no matter what fine they demand, offer 200k. 200k no matter what. They might make you sweat it for a few minutes, but 200k will get you on your way and you won’t lose your bike.
I’ve lived here seven years btw. Where are you living?
Ohhh ya… Car is a different story, they know, or at least think you’ve got money…