One strike ure out rule is a bit harsh. Everyone makes mistakes and I know of a LOT of guys who push the limits a little too tight for comfort.
Alcoholism is a disease and should be treated as such. A hard rap on the knuckles with a strict monitoring of a rehab program should hopefully set straight most guys. However, if it reoccurs then obviously the poor chap is in the wrong industry and will be (and should be) shown out the door.