I agree that some get carried away with anti alcohol legislation but then again they've seen the resulting bloodshed and misery of drinking and driving. Until people become more responsible about drinking/flying/operating any machine, etc - beer or ice wine or anything - they should not be driving. Period.
I believe that all the drinking laws actually contribute to drunken driving. This is because these laws create a climate where one wants to "drink as much as possible when one can". Thus we have underage teens drinking unsupervised in places that they usually have to drive out to. Or adults on their way to a place where drinks are either limited or not allowed will tend to drink heavily before going to these places.
I am totally with you on the drinking and driving and if this law would prevent it maybe I could see it passing, but this is not going to prevent people who would normally drink and drive from stopping.