This has been happening in Thailand for ages mate, why are you surprised?
tbh I don't know how they pick their targets. Local police know what's what so when the big boss Pol Maj Gen from Region 2 comes in to "take over" does he tell the locals to cough up a few names for show or does he get his boys to do some actual legwork?
Clubs that flaunt closing times are a good target for drug raids. Once you get on the drugs you want to party all night so it makes sense that you'd find more drug takers at such places. As opposed to say, the Christian Science Reading Room.
I stopped taking illicit drugs a long time ago and even if I were to start again these Thai clubs don't float my boat. So I have no reason to try and figure out what the best tactic is if you're caught up in a raid. But from what I've picked up over the years you don't have much of a choice, especially in this case where the Regional police big boss is on some kind of holy mission.