The Government has imposed a ban on the sales of alcohol this weekend from 6 pm Saturday until 12 midnight on Sunday for a referendum vote to change the Constitution.
The voting booths open at 7am on Sunday and close at 4 pm.
So the powers that be want their citizens sober when they cast their votes on Sunday, and do not want any trouble after the voting booths close at 4pm, hence no sale of alcohol until midnight.
This is Thailand we love it!!