I agree with the discussion. I had a situation in one of my project that i a worked with at the beginning of my career. I was in the quality control department, where we test some required number of batches coming out of the production site and release that batches, with the test protocol for each specification in the product specification list. One of the senior member was on family vacation for six months. Due to lack of experience in certain critical testing , my manager will not allow me or my peer colleague to work on those testing. I decided to talk to my manager for cross-training . I talked and she agreed. My manger decided to cross-train every person in the laboratory, so that they can avoid this situation.