For myself I have a strict no drinking rule when I am driving. I believe that in Germany, the police can prosecute a car driver, who falls asleep drunk in the back of his car. Whereas I can appreciate the point that it is better that the police always have the power to prevent drunk driving, I have some misgivings about that one. It could well motivate someone, who would otherwise have laid down, to take the risk and drive.
When I was on the road as a busker, I stayed dry when I was in my bus unless there were other buskers parked around. You never know who is going to come knocking on your door in the middle of the night. So I wanted to be able to drive away at any time at all if I needed to.