Yes, it is, even if you can´t see it. What it delivers are information about that you should not drink and drive as well as a message to keep foreigners safe when driving in Thailand. I know that thousands of Thais are driving drunk every day, but that is no excuse. Anyway, as a foreigner, you do not want either accident or fines in Thailand, so it also serves as a deterrent for some people that has not been drinking away their intelligence. That you do not get it can only be based on two things. Either you do not drink and drive, or you drive drunk and do not realize the danger and wrong in that before you get badly hurt.