Having studied in Culinary Arts and then chefing in some expensive restaraunts, I can say I have never seen it done. I am not naive enough to think it does not happen, however. I think it is horrible for anyone to do this. The public is trusting the food industry workers to give them food that is clean and well cooked. Anybody who would do such a thing, for any reason, should be fired right away. They do not belong in the food industry.