Thank you, samebb, for some more interesting insights.
In hindsight I figured out that several of the boys I had had sex with for money were "parked" in Bangkok or Pattaya while visa for Europe or America was processing. So having a Farang boyfriend, who supports the boy financially and arranges for him to come to Europe or America, is no hindrance for a quicky for some extra cash. (Says a lot about the character of the boys to which this applies.)