Final answer:
The truth of the statement regarding self-checkout stations staff requirements varies by store policies and local laws; without specific details from a particular store or legal guidelines, it cannot be asserted as universally true or false.
Step-by-step explanation:
The statement that at self-checkout stations, all staff members must be at least 18 years of age, Smart Serve certified, and know the store policy could be true or false depending on the specific store's policies and local laws. In general, businesses might require staff overseeing self-checkout stations to meet certain age requirements, have specific certifications (like Smart Serve for alcohol sales), and be knowledgeable about store policies for a variety of reasons, including legal age requirements for the sale of restricted items, and understanding of company procedures to assist customers effectively. However, the provided references regarding the market's self-scan checkout aisles and employment restrictions for construction workers and salespeople do not directly indicate that these specific requirements must be in place for all self-checkout station staff. Therefore, without specific information from a particular store or legal guidelines, we cannot definitively state whether the claim in the question is universally true or false.