The better custom cutters that I knew had strict rules for their crew. Usually they were very strict about no drinking on or off the job. Some where very strict about when and where the crew could smoke.
One operator told me that if they were shut down for rain or some other reason, he hired out his crew to local farm equipment dealers to assemble equipment that came in knocked down from the factory - to keep them from wandering off and getting into trouble.
He also had a firm rule that if anyone ever quit him, he would never hire them back again for any reason. He would let a combine set idle rather than hire back a guy. Word got around, so when he hired a crew at the start of the season, he knew they would stay with him through the run.