First of all, got to love Vietnam Traffic police (Công An Nhân Dân Việt Nam)
it has been rated most corrupted organisation in the world :)

One thing special in Vietnam is that traffic police don't want to touch you if they know your westerner.. so that means they really don't care if you ride your bike without license or even helmet!!
what in my opinion is little stupid but hey! that is their life not my.

At the moment i have had two incident with the police, both times they did not realise that i was westerner until they notice my face was little too white ;)

Case one.
Was driving back to home in one evening and i did notice that up in the road traffic police was working hard to make week pay from the local people, while i was coming towards them one of them might have picked up my lovely exhaust note and decide to hop middle of the street to "catch" me, I saw him coming and taught to myself "Hell no.. I'm not stoping" I continue to approach this police officer and and tried to manoeuvre left.. no luck at all.. but then one meter before him he realised that i am westerner and his eye's just rolled up towards the stars and I gently drove my bike around him.. You can just imagine how I did laugh after that while driving away! His face expression was so funny.

Case two.
This actually happened this week,
I was coming home after nice dinner with my wife and we stopped to traffic lights (what locals do if they feel like it) and while we waited there that minute just before light is about to turn green police walks behind me and grasp my shoulder just before he realise that his big payday has gone and just say "ou, westerner" and walks away.. and i started my bike and drove away..

These are the cases where i have gotten in the Vietnam with my motorcycle.

Mind you that all of these cases I have driven by the "rules" but then again sometimes looking these police stopping people over there does not seem to be too much logic why they stop "violators"

One reason that these incidents has been happening might because of my full face helmet.
I might need to invest to some sort "fighter" plane helmet style what can reveal my westerner face

Only thing what i do continue break is that i do not keep my bike papers with me ever! there are few reason for this.

One is that possession is law in here, so if i store my bike papers in the bike and some jackass would stole it they would basically own my bike

Secondly i could carry them with me but as they make them bigger than wallet i would always need to change papers to that jacket or pants what i would be using..

While moment Vietnamese police don't (usually) stop westerner is simple economical.. they do not speak English enough and while they could make westerners pay little bit more it's not worth to sacrifice valuable time, as he can work his magic to locals and get that little money without too much trouble,
besides westerners could cause a lot of trouble if they complain, what locals will never do.

this is my two cents in this matter.

Police in Thailand is totally different story :)