Let me educate you, xdm, that electronic cigarettes are indeed illegal in Thailand (so those doing electronic cigarettes in Thailand are really making a lot of money) but it's not necessarily a five-year sentence. Generally, they will just confiscate it, or you can throw it away, or hide it in your car, or just don't let them see it...

From normally finishing drinking and having a midnight snack, taking a taxi back to the hotel, to suddenly being intercepted by a team of Bangkok police, the Grab driver raised his hand and looked back at me, and I was completely bewildered. Then the car door was pulled open, and my heart raced, my heartbeat stopped as several flashlights shone on my face.
The police took a defensive stance and asked me to get out of the car. Then they asked where I was from, after which they waved the driver to leave. One officer was always on guard, one was searching me, and another used a phone translator to tell me not to move and to cooperate with them.
They searched me thoroughly and found my phone, cash, hotel key card, and e-cigarette. At that moment, I was ready for them to divide the cash among themselves and let me go because they started counting the money. Unexpectedly, after counting, they gestured for me to put it back in my pocket.