Final answer:
Storing unused checks in the vault reflects the internal control procedure of restrict access, ensuring authorized personnel can access them only.
Step-by-step explanation:
The internal control procedure that is reflected by storing unused checks in the vault is restrict access. This procedure ensures that only authorized personnel have access to the checks, reducing the risk of theft or misuse. By storing the checks in a secure location such as a vault, the company can tightly control who has access to them, making it easier to detect any unauthorized activities.