Final answer:
A competent person may not need to test excavated soil in a controlled archaeological excavation if the focus is on preserving artifacts in their original contexts and modern techniques are used to minimize disturbance.
Step-by-step explanation:
The question you've asked pertains to when a competent person does not have to test the excavated soil. This scenario could be related to archaeological practices and safety measures in controlled excavations. In controlled archaeological digs, a competent person may not need to test the excavated soil if the focus is on preserving the in situ context of artifacts.
During controlled excavations, safety measures are paramount. Artifacts are often left in their original place, also known as in situ, to provide context and aid in interpretation. Archaeologists carefully catalog, map, and record items through photographs or drawings before disturbing their findspot. Modern techniques and precision instruments have made these excavations less intrusive than in the past, minimizing the need for soil testing unless it pertains to understanding the strata or preserving the find.