Truck driver: Knowledge of the travelling salesman problem. Algorithms in general to find optimal routes. A little programming knowledge to help with automating their excel sheets to record expenses.
Cook: OOP as it is applied to a kitchen and its staff: are there more efficient ways to divide roles and responsibilities between different jobs in the kitchen, or are the defined roles (line cook, sous chef, etc) already at local optimum. Database programming can help with inventory management, etc...
Welder: (Disclaimer: I have absolutely zero knowledge of welding) FLow charting work process to find more efficiency. Decomposing a task to be completed into more effective sub tasks. Using Big O concepts to help with estimating how long a job will take to complete using different methods.
I think there is a lot programming can teach outside of being able to program a computer.