merely stating my experience on several occasions. Not only me but I know many others entered with vapes and liquid - never an issue. Most of the customs people aren’t in it for a quick buck (unlike the local policeman in Pattaya) and I get the impression they are happy to let it go if not in large quantities.
Why? Taken in my vape dozens of times over the years. I often have extra liquid in my case also. Never caused any issue when bags went through x ray on occasions.
Does seem to be totally random to be fair. I know some who have never been asked but know others who have been asked regularly. I agree, must be the honest smile 😉