Before conducting an inspection, what should an inspector ensure about the customer when a CNG tank is involved?

When conducting an inspection of a vehicle that has a Compressed Natural Gas (CNG) tank, it is crucial for the inspector to ensure that the customer is present during the inspection. This presence facilitates communication about the specific requirements and procedures involved in inspecting CNG systems, which can differ from those of conventional fuel systems. Furthermore, having the customer on-site allows the inspector to address any questions or concerns related to the CNG tank and ensures that the customer is informed about any findings or issues that may arise during the inspection process. This practice helps maintain transparency and trust between the inspector and the customer, which is essential for successful vehicle inspections, particularly with specialized systems like CNG tanks.

Other options, such as requiring proof of purchase, ensuring the vehicle is clean, or asking for previous inspection results, do not address the unique safety and procedural elements involved specifically with CNG systems, and therefore are not as critical for the inspection process.