the last time I was in Bangkok when there is an official ban on all sales of alcohol was during the weekend when they were holding pre-election for early voters. most clubbing places are closed. The authority is presumably worried that Thai citizens would get too intoxicated to wake up to vote.
The gogobars in Soi Cowboy and Nana Plaza are open but they only sell coke and orange juice (at about the price as the beers and alcohol and which hardly anyone will order on any other days). it was quite a refreshing experience to be in a nightlife venue looking at semi-naked girls and sipping orange juice.
another club that was doing business on that night was SPICY. but since it was an after-hour pick-up clubbing place and open till 4 -5am, which officially is illegal anyway, I suppose the authority is inclined to close one eye.
but the occasion is political election and only bros in Bangkok can confirm if they will do the same for holidays of religious observance.