What is the primary concern behind the use of the back door after dark?

The primary concern behind the use of the back door after dark is asset protection. This focus stems from the need to ensure the safety and security of the business's physical assets, which include inventory, equipment, and cash. Using the back door during night hours can help minimize exposure to potential theft or unauthorized access, thus safeguarding the restaurant's valuable resources.

Given that other options may seem relevant in different contexts, they do not address the main concern when it comes to accessing the premises through the back door at night. Guest access primarily hinges on customer service and experience, while employee comfort relates to workplace well-being. Health regulations focus on sanitation and safe food handling rather than security protocols regarding entry points and asset protection. Therefore, the emphasis on protecting assets aligns most directly with concerns surrounding after-dark access through the back door.