In our club, we have never to my knowledge had a flier show up to fly with alcohol on his breath. And there are several non-drinkers in the club who can smell alcohol on someone's breath from 4 or 5 feet away.
A couple of commercial pilots in the club hold that the 24 hour rule they live up to is a minimum.
Our basic rule is that if you want to have a beer at the field, pack up and put away your equipment before opening the first can. Your flying day is over. We enforce this.
One of the long time clubs in our area folded due to noise complaints from new developments a few years ago. A number of the members joined our club. About half quit the first year over this. Their no drink and fly rule meant you put down your beer before picking up the transmitter and flying. They also had a lot more accidents than we did, even though they only had about 3/4 our number of members.