Final answer:
Skin abrasions indicate an unsafe action by the nurse who applied the restraints.
Step-by-step explanation:
When assessing the client with the restraints, the observation by the charge nurse that indicates the nurse who applied the restraints performed an unsafe action is skin abrasions. Skin abrasions suggest that the restraints may have been applied too tightly or improperly, causing harm to the client's skin. This could lead to further complications and potential infection.