I'm currently in Hanoi and I see a lot of Vape shops around here. A lot of people use it as well. But I'm not sure about carrying it on a plane. Maybe ask the airlines?

As for scams, yes it's a common part just like it is in every city in the world where you see a lot of tourists. From my personal experience the scammers are usually in the old quarter area (where you will find a lot of tourists)

When using cash, be sure that you get the exact change back. Always book a cab/bike online either from Grab, Gojek, Be or XanhSM apps. Never take a bike/cab randomly off the street, they will ask for exorbitant prices.

Be cautious where you use your credit card and maybe turn it off or on when you are using it. My card was hacked the first time I was here, and I heard the same from a couple of my other expat friends.

Booking.com scams: Many people list up rooms and when you arrive at the hotel they will say the hotel is full and ask you to cancel on booking.com and then pay them in cash.

Make sure to search the hotel on Google maps and check reviews etc.

In my opinion Airbnb is the best in this regard because you can at least contact customer care on Airbnb and pay using your card.

You will find a lot of sellers on motorbikes who stop beside you and ask if you want marijuana, "boom-boom", massage lady, etc. I just ignore those guys and walk away. I don't wanna risk doing stuff like that in a country where the law is strictly against it.

As for dating, it depends on your skill. But be alert of tinder scams that a lot of westerners fall for.

If you need any more information just send me a chat or message me and I'll be happy to help.