Kindness or walkaway...

Past is past 
Better try next time!

No reason to place yourself in danger. It will become a learning experience for him. On my 1st trip here I ended in a fake taxi even after being told he was a real taxi. Now I know where to take metered taxi from.

Don't worry about it man, this is how every foreign traveler finds their way in a new country/city..
If none of us had been scammed by a taxi/ tuk tuk drivers on our visits around the world, we would never learn the true cost... and we would never have funny stories.

Also your better not to stick your nose into a fake taxi drivers business.
The amount of Dong that the tourist was losing out on, is tiny compared to bringing the anger/ violence towards you. The tourist was in no danger of harm, just going to lose out on some Dong/dollars

Don't worry about it but thanks for caring enough to post the message.

You did a very good job by posting their nasty tactics here.

I guess a lot of people will aware of this in the future.

Cheers.

Welcome to V.V.

Nguyen.tien,

If you had tried to help this man, he wouldn't have understood and perhaps would have thought you were a problem. In this case the man was not in physical danger so you did exactly the right thing. The airport should have security people to deal with the Taxi nonsense. My first time here I paid 200 thou when I should have paid 100 thou,  I have been scammed a thousand times since at the market, by street venders, xe om drivers and by pretty girls. Unfotunately expats are continual targets and there is no short supply of vendors lacking integrity. Love your empathy, we need more like you.

its is good for you that you worry, but foreigner must learn the rules  so he will know better next time.

The danger you would have put you self in is far greater than the amount he would've been overcharged and lets face it, if he can afford to stay at that hotel he could afford the increased pricing.
Remember they're criminals in fake taxis and not real taxi drivers so they will resort to all means of violence if you are posing a threat to their illegal activities.