What is the exception to holes in the exhaust system that would not result in vehicle rejection?

Holes made by the manufacturer for drainage purposes are an exception in the context of vehicle inspections. This is because manufacturers sometimes design specific openings in the exhaust system that allow moisture to escape. These holes are an integral part of the system's design to prevent corrosion and maintain proper drainage, which is essential for the longevity and functionality of the exhaust system. As such, these manufacturer-intended openings do not compromise the exhaust system's integrity or performance, thus they do not warrant a rejection during a vehicle safety inspection.

In contrast, modifications made for sound modification or performance enhancement typically alter the exhaust system's intended design, which can lead to emissions and noise issues. Additionally, holes caused by normal wear and tear may indicate a level of deterioration that affects the exhaust system's performance and safety, resulting in a rejection during inspection.